Core Usenet Concepts

The foundational vocabulary of Usenet: what newsgroups are, how the hierarchies are organized, what an article actually contains, and how posts travel from one server to another. Start here if terms like Message-ID, crosspost, or propagation are unfamiliar. Everything else in this glossary assumes the ideas defined in this section.

62 terms in this category.

Usenet: A distributed discussion system launched in 1980, a decade before the web. Articles are posted into named newsgroups and copied from server to server rather than held in one central place, so no single operator controls the network or can take all of it down. Reading requires an account on a news server and client software. Text discussion dominated early; binary file distribution now accounts for nearly all traffic.
Netnews: An older name for Usenet, common in early documentation, RFC titles, and the names of the software that carried the traffic. The word covers both the articles themselves and the machinery that moves them between sites. It survives in the news.* hierarchy and in a few standards documents, but almost nobody uses it in conversation now; Usenet won out as the everyday term.
Newsgroup: A named channel that articles are posted to, written as dot-separated labels running from general to specific, such as comp.lang.c or alt.binaries.sounds.mp3. Each server decides independently which groups it carries and how long it keeps their articles. A group is not a folder on one machine; the same group exists on thousands of servers at once, each with its own article numbering and retention window.
Article: The unit of content on Usenet, equivalent to a single message. Each one carries a block of headers, a blank line, then a body, and is identified network-wide by its Message-ID. Articles move between servers as complete units and are never modified in transit apart from a few routing headers. A large binary upload is split across thousands of articles that a newsreader reassembles after download.
Post: Both the act of sending an article to a newsgroup and the article that results. A posting server accepts the article, assigns it a local number, and hands it to its peers. Unlike a web forum message, a post cannot be edited once it has left the originating server; a correction requires a follow-up or a Supersedes header, and neither propagates reliably to every site.
Thread: A chain of articles linked by replies, assembled by the newsreader from References headers rather than stored as a structure on the server. Each follow-up lists the Message-IDs of its ancestors, so a client can draw the tree even when articles arrive out of order or some never arrive at all. Subject lines usually carry a Re: prefix, but References is what actually determines placement.
Subject Line: The header giving an article its title, shown in group listings and used by readers to skim. On text groups it summarizes the message. On binary groups it does structural work instead, encoding the release name, the file name, and a part counter in a form such as [01/42], which is what indexers and newsreaders parse to group thousands of segments back into single files.
Follow-up: A reply posted back to the newsgroup rather than mailed privately, carrying the parent's Message-ID in its References header so clients can thread the two together. Convention prefixes the subject with Re:. Follow-ups go to whatever groups the Followup-To header names when one is present, which stops replies to a crossposted article from scattering across every group in the original Newsgroups line.
Crosspost: Posting a single article to several groups at once by naming them all in the Newsgroups header. The server stores one copy and references it from each group, so a crosspost costs far less disk and bandwidth than separate posts, and readers who follow more than one of the groups see it only once. Naming more than a handful of groups is treated as abuse and is a common spam signature.
Followup-To: A header that redirects replies to groups other than the ones an article was posted to. An announcement crossposted to five groups can set Followup-To to a single discussion group so responses collect in one place. The special value poster asks that replies go by email instead of to the network. Newsreaders honor it automatically, though it is advisory and can be overridden before sending.
Newsgroup Hierarchy: The tree structure encoded in group names, read left to right from broadest to narrowest: rec.arts.movies.reviews sits under rec, then arts, then movies. The leftmost component names the hierarchy and determines who administers it, what procedure creates groups within it, and frequently whether a given server carries the branch at all. Servers subscribe to or drop whole hierarchies rather than managing groups one at a time.
Big 8: The eight hierarchies governed by a formal creation process: comp, humanities, misc, news, rec, sci, soc, and talk. A proposal passes through public discussion and a vote before a newgroup control message is issued, which keeps the group list curated and small compared with alt.*. Nearly every server carries all eight in full. Binary groups are absent from them by policy rather than by accident.
alt.* Hierarchy: Created in 1987 as a deliberate escape from Big 8 procedure. Anyone can issue a newgroup control message for an alt.* group, and each administrator decides independently whether to honor it, so the namespace is enormous, uneven, and littered with groups that never carried a single post. Because no vote stood in the way, binary distribution settled here, almost entirely under alt.binaries.*.
comp.* Hierarchy: The Big 8 branch for computing: hardware, operating systems, programming languages, networking, and applications. Groups such as comp.lang.c and comp.os.linux.misc carried heavy technical discussion through the 1990s, and a handful remain among the more active text groups anywhere on Usenet. Like the rest of the Big 8, comp.* is text only, and posting encoded files there breaches the group charters.
rec.* Hierarchy: The Big 8 branch for recreation, hobbies, and the arts, running from rec.food.cooking to rec.sport.cricket to rec.music.classical. It was among the largest branches by group count and by volume before web forums pulled the audience away. Charters restrict it to discussion, so images and audio belong elsewhere, which is why rec.* stayed almost entirely text through its whole history.
sci.* Hierarchy: The Big 8 branch for the sciences, holding groups such as sci.physics, sci.math, sci.astro, and sci.crypt. It drew working researchers and graduate students, and some archived threads are still cited decades later. Traffic fell away once preprint servers and specialist mailing lists became normal. As with every Big 8 branch, sci.* is text only and has no binary groups beneath it.
soc.* Hierarchy: The Big 8 branch for societies, cultures, and communities, with groups such as soc.culture.japan and soc.history.war. National and diaspora communities gathered here in quantity before the web offered alternatives. Several soc.* groups are moderated, which was one way of keeping long-running disputes contained. The branch is text only and new groups within it follow the standard proposal and vote procedure.
talk.* Hierarchy: The Big 8 branch set aside for contentious argument: politics, religion, and similar perennial disputes. It exists partly so that flame-prone subjects had somewhere to go, and so that an administrator wanting a quieter feed could drop the whole branch in one line of configuration. Groups such as talk.origins produced long-lived reference FAQs. Present-day volume is thin and heavily diluted by spam.
misc.* Hierarchy: The Big 8 catch-all for subjects that fit nowhere else, including misc.jobs.offered, misc.kids, and misc.consumers.house. It absorbs proposals that cannot reasonably be placed under comp, rec, sci, soc, or talk, making it the most heterogeneous branch by design rather than by neglect. Creating a group here still requires the full Big 8 process, and the branch carries text only.
news.* Hierarchy: The Big 8 branch about Usenet itself: server software, administration, group proposals, and network policy. news.announce.newgroups carries formal proposals and results, news.answers archives periodic FAQ postings, and news.software.nntp discusses server implementations. Newcomers were traditionally pointed at news.announce.newusers. Several groups here are moderated, since between them they form the written record of how the network governs itself.
humanities.* Hierarchy: The newest Big 8 branch, added in 1995 for literature, philosophy, classics, and the fine arts, with groups such as humanities.classics and humanities.lit.authors.shakespeare. It was carved out to give scholarly arts discussion a home distinct from rec.arts. Group counts and traffic have been modest from the beginning, so servers carry the entire branch without any meaningful storage cost.
Regional Hierarchy: A hierarchy scoped to a country, language, state, city, or single organization: de.* for German-language groups, uk.* for Britain, or a university's internal tree. Servers outside the region routinely decline to carry these branches, so limited propagation is the intent rather than a fault. Each regional hierarchy sets its own creation rules, and several remain busier than their Big 8 counterparts.
Binary Newsgroup: A group carrying encoded files rather than conversation, nearly always under alt.binaries.*. Articles hold yEnc-encoded segments that a newsreader reassembles into the original file. Because one release can span thousands of articles, these groups produce the overwhelming majority of Usenet's daily volume, measured in tens of terabytes, and they are what the retention and completion figures on a provider's specification sheet actually describe.
Text Newsgroup: A group carrying readable discussion rather than encoded files, which covers the whole Big 8 and a large slice of alt.*. Volume is low enough that servers keep text groups far longer than binaries, commonly a decade or more, because the storage cost is negligible. Providers therefore quote text retention as a separate and much larger number than binary retention.
Moderated Newsgroup: A group where submissions are mailed to a moderator instead of propagating at once. The moderator approves an article by adding an Approved header and reinjecting it, and servers reject anything in the group that lacks that header. The mechanism predates web moderation tools and cut spam sharply where it was used, at the cost of delay and dependence on volunteers who often drifted away.
Unmoderated Newsgroup: A group in which any article reaching a server propagates without review, which describes the large majority of Usenet. With no gatekeeper, filtering falls to the reader through killfiles and to the administrator through spam-filtering software such as Cleanfeed. The absence of moderation is the main reason open groups filled with automated junk once bulk posting became cheap in the mid-1990s.
Control Message: An ordinary article carrying a Control header that tells servers to act rather than merely file it. Defined actions include newgroup, rmgroup, checkgroups, and cancel. Every server decides for itself which control messages to obey and from which senders, so an rmgroup that deletes a group at one site may be logged and ignored at the next. Forgery concerns made manual review the norm.
newgroup Control Message: The control message asking servers to create a group, carrying the group name, its moderation status, and usually the charter in the body. In the Big 8 it is issued only after a proposal has passed a vote; in alt.* anyone can send one. Because forged newgroups were once common, most administrators now process these by hand or accept them only from a trusted signing key.
rmgroup Control Message: The control message asking servers to remove a group. Since a forged rmgroup could wipe groups across the network, almost no server acts on one automatically today; administrators queue them for review or honor them only when signed by a recognized hierarchy maintainer. Articles in a removed group normally stay on disk and expire on the usual schedule rather than being deleted immediately.
checkgroups: A control message carrying the authoritative list of groups in a hierarchy, each with a one-line description and a moderation flag. Administrators compare it against the server's active file and add or drop groups to match, which is how a hierarchy distributes its canonical group list. The Big 8 board issues one periodically. Most sites process it semi-automatically and review the deletions before applying them.
Cancel Message: A control message asking that one article, named by Message-ID, be deleted from servers carrying it. Nothing in the original design verified the sender, so cancels were trivially forged and were used both to erase other people's posts and, in bulk, to fight spam. Most servers now discard cancels outright or accept them only when a matching Cancel-Lock proves the original poster sent it.
Supersedes Header: A header naming an earlier article, by Message-ID, that the new one replaces. Servers honoring it delete the old article as the replacement arrives, which is as close as Usenet comes to editing a post. Its main legitimate use is periodic FAQ postings, where each fresh copy supersedes last month's. Like cancels it can be forged, so a good many servers ignore the header entirely.
Expires Header: A header suggesting a date after which an article may be removed. Servers treat it as advisory: most apply their own retention policy and ignore the request, though some honor it so that short-lived announcements do not linger. Setting a distant Expires date does not extend an article's life on a server whose own expiry runs shorter, which is the usual source of confusion about it.
Message-ID: The globally unique identifier carried by every article, written in angle brackets as a local part, an at sign, and a domain. Servers deduplicate with it: an article whose Message-ID has already been seen is refused instead of stored twice, which is what keeps a densely peered network from multiplying copies. References threads with it, cancels name their target with it, and NZB files address segments by it.
References Header: A header listing the Message-IDs of the articles a follow-up descends from, oldest first. Newsreaders build threads from it, so a reply lands under its parent even when the subject has been rewritten. Clients often trim very long chains to keep the header a reasonable size. Threading collapses when posting software omits References, which is why replies from misconfigured clients appear as new top-level articles.
Xref Header: A header added by a server listing the group and article-number pairs a crossposted article occupies on that particular machine, such as comp.misc:4123 alt.test:9981. Newsreaders read it to mark a crosspost read in every group at once instead of showing it repeatedly. The numbers are local to the server that wrote the line and mean nothing at all on any other server.
Newsgroups Header: The header naming which groups an article is posted to, comma-separated with no spaces between them. Listing more than one makes the article a crosspost, stored once and linked from each group named. Servers reject articles that name only groups they do not carry, and many cap how many groups a single article may list, since long Newsgroups lines are characteristic of bulk spam.
From Header: The header carrying the poster's display name and address, formatted like an email From line. Nothing authenticates it, so the value is frequently forged or deliberately mangled with an unroutable address such as [email protected] to frustrate address harvesting. On binary groups the From value is usually a throwaway alias, which indexers record next to the release name as the poster of record.
Organization Header: An optional header naming the poster's employer, university, or service provider. Newsreaders usually fill it from server configuration, which is why articles injected through one provider tend to share an identical Organization string. It performs no technical function and is purely descriptive, though it once gave a rough hint of where a poster was connecting from. Plenty of modern clients omit it.
Path Header: A header recording the chain of servers an article has already passed through, written as hostnames separated by exclamation marks and read right to left from the injecting site outward. Each server prepends its own name and refuses to feed the article back to any host already listed, which is how the network prevents loops. Tracing a Path is the standard first step in diagnosing propagation problems.
Distribution Header: A header limiting how widely an article should travel, using a keyword such as local or a regional code. Servers that honor it decline to pass the article beyond the named scope, which suited classified ads, campus notices, and other content of no interest further out. Support has always been patchy and many servers ignore the header, so it is seldom relied on today.
Date Header: The header giving the time an article was posted, in the same format email uses, including a timezone offset. Newsreaders sort and expire on it and indexers report release age from it. The value comes from the posting client, so a wrong clock produces articles that sort far into the past or future; servers commonly reject dates that fall outside a plausible window.
Lines Header: An optional header stating how many lines the body contains. Readers once used it to judge whether a post was worth fetching over a slow dial-up link, and it still appears in overview data beside the byte count. Nothing recomputes the number in transit, so it is not authoritative, and a fair amount of current posting software omits it in favor of the byte count.
User-Agent Header: The header naming the software that posted an article, giving a client name and version. It displaced the older X-Newsreader and X-Mailer headers in common practice. The value is informational and freely settable, so it identifies posting tools only loosely, but it helps administrators spot automated bulk posters and helps diagnose clients that mangle threading, character sets, or encoding in recognizable ways.
Article Number: The sequential number a server assigns an article within a single group, counting up from one and never reused. NNTP commands such as ARTICLE and STAT accept it as shorthand for a message in the currently selected group. Numbering is local to each server and each group, so the same article holds different numbers everywhere, and a .newsrc copied between providers marks the wrong things read.
Overview Database: A per-group index holding a few fields from each article: subject, author, date, Message-ID, References, byte count, and line count. Servers maintain it so clients can list a group without fetching whole articles, which is what makes opening a group of millions of posts practical at all. The XOVER and OVER commands read it, and bulk header downloading in binary readers is overview retrieval at scale.
Article Header: The block of name-value lines at the top of an article, ending at the first blank line. Required fields include From, Subject, Newsgroups, Date, Message-ID, and Path, and servers add or rewrite several of them in transit. A long value may be folded across continuation lines that start with whitespace. Everything needed to route, thread, and index an article lives in this block.
Article Body: Everything after the blank line that closes the headers. On text groups it holds the message and any signature; on binary groups it holds one yEnc-encoded segment of a much larger file. During transfer a line containing nothing but a period marks the end of the body, which is why leading periods inside the content are doubled by the sender and undoubled by the receiver.
Propagation: The spread of an article from the server it was injected on to that server's peers, and outward from them until it reaches most of the network. Well-connected servers see a new article within seconds; thinly peered ones lag or never receive it. Incomplete propagation is a routine cause of missing segments, since a release can be whole at one provider and short at another.
Article Expiry: The removal of articles once they pass a server's retention window or the spool runs out of room. Policies are set per hierarchy, so text groups may be kept for years while binaries roll off on a fixed schedule. Expiry explains why a release that downloaded cleanly a year ago now returns 430 errors on every segment: those articles are gone, not merely misfiled.
News Feed: The flow of articles between two servers under an agreement covering which hierarchies move in which direction. Feeds are configured per peer and may be full, meaning everything the sender carries, or filtered down to text-only or a named subset of groups. How many feeds a provider takes, and how reliable each one is, directly determines the completion its subscribers see on busy binary groups.
Peering: The arrangement under which two news servers exchange articles directly. Each side offers what it has, the other refuses anything whose Message-ID it already holds, and the Path header keeps articles from circling back. Dense peering shortens the route between a poster and a reader, improving both propagation speed and completion; a provider with few peers shows visible gaps on high-volume binary groups.
News Server: The machine that stores articles, exchanges them with peers, and answers NNTP commands from clients. Large installations split the roles, with transit servers handling feeds between providers and reader servers taking subscriber connections. INN and Diablo are the long-standing implementations. What a server carries, how long it keeps it, and how many simultaneous connections it permits define the service a subscriber actually receives.
Newsreader: Client software that connects to a news server, lists groups, fetches articles, and posts. Text readers such as slrn or a mail client's news mode present threaded discussion. Binary readers take an NZB file, open many connections at once, pull segments in parallel, and pass the result to repair and unpack stages. The two kinds share a protocol and very little else in the way of interface.
Newsgroup Charter: The statement of a group's topic and rules, written during the proposal that created it and distributed in the body of the newgroup control message. A charter defines what counts as on-topic, whether the group is moderated, and sometimes whether encoded files are permitted. It carries no technical enforcement whatsoever, so it matters only as far as readers and moderators choose to hold posters to it.
Group Creation: The process of adding a group to the network. In the Big 8 it runs through a Request for Discussion, a comment period, a vote, and finally a newgroup control message from the management board. In alt.* there is no formal procedure at all: anyone may issue the control message and each administrator decides whether to honor it, which is why many alt groups exist on only a few servers.
.newsrc: The client-side file recording which groups a reader subscribes to and which article numbers have been read in each, stored as a group name, a subscription marker, and number ranges such as 1-4023,4025. Because those numbers are per server, copying a .newsrc to a different provider marks entirely the wrong articles read. Modern readers keep the same information in their own databases instead.
Subscription: A newsreader's record that a group should be displayed and tracked, held locally in .newsrc or an equivalent database. Nothing is registered on the server, so subscribing costs nothing and the provider never sees it. The same word also names a paid account with a Usenet provider, which is a wholly separate thing: access to a server rather than interest in a particular group.
Quoting: Including part of the article being answered, each line prefixed with a greater-than sign, so that a follow-up reads sensibly on its own. Convention is to keep only the passages actually being addressed and to write beneath them. Quoting an entire long article to add one line at the top is a standing complaint on text groups; cutting the quote back down is called snipping.
Attribution Line: The line introducing quoted text in a follow-up, naming who wrote it, in a form such as On Tuesday, A. Poster wrote. It keeps authorship traceable when a thread runs several quoting levels deep. Newsreaders generate it automatically from the parent article's From and Date headers. Editing an attribution so that words are credited to the wrong person is treated as a serious breach of netiquette.
Signature Block: The block appended to the end of an article holding a name, contact details, a project URL, or a quotation. Convention separates it from the body with a line containing two hyphens and a space, which tells newsreaders to strip it automatically when quoting. Four lines is the traditional limit and longer ones draw complaints. Automated binary posting tools generally omit the block altogether.
Dot-Stuffing: The transport convention that keeps article bodies from being cut short. Since a line holding a single period signals the end of an article, any body line that begins with a period gets a second one added by the sender and removed by the receiver. The doubling is invisible when both ends implement it; a client that fails to undo it silently corrupts encoded binary data.

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Core Usenet Concepts

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