The later peer-to-peer networks operate on a similar principle, but for Usenet it is normally the sender, rather than the receiver, who initiates transfers.
Usenet was designed under conditions when networks were much slower and not always available.
It was originally built on the "poor man's ARPANET", employing UUCP as its transport protocol to offer mail and file transfers, as well as announcements through the newly developed news software such as A News.
The name Usenet emphasized its creators' hope that the USENIX organization would take an active role in its operation.
Usenet resembles a bulletin board system (BBS) in many respects and is the precursor to Internet forums that are widely used today.
Discussions are threaded, as with web forums and BBSs, though posts are stored on the server sequentially. One notable difference between a BBS or web forum and Usenet is the absence of a central server and dedicated administrator.
The articles that users post to Usenet are organized into topical categories known as newsgroups, which are themselves logically organized into hierarchies of subjects.
For instance, and sci.physics are within the sci.* hierarchy, for science.
When a user subscribes to a newsgroup, the news client software keeps track of which articles that user has read.
Tom Truscott and Jim Ellis conceived the idea in 1979, and it was established in 1980.
Users read and post messages (called articles or posts, and collectively termed news) to one or more categories, known as newsgroups.
Many sites on the original Usenet network would connect only once or twice a day to batch-transfer messages in and out.
This is largely because the POTS network was typically used for transfers, and phone charges were lower at night.