Asstr.org

Alt.sex.stories text repository, most often known by its acronym asstr.org, is a huge, largely unorganized collection of erotic stories, 450,000 as of 2015. "Alt.sex.stories" refers to a very early form of the Internet, perhaps the earliest, Usenet groups, currently owned by Google Groups. Without a central server, messages posted by any user were automatically sent to any user who wanted to receive them, and who started up his Usenet reader program (now typically handled within a browser). Postings were categorized into groups. Usenet is moribund though it still survives, and has around 500,000 postings a day, a large number of which are spam (advertisements).

There is no central site that archives everything on asstr.org; that would be prohibitive. Partial access is offered by some commercial sites. Access to text-based postings, without the more-expensive-to-store binary files (pictures, videos, music), is offered by Google Groups.