Short-hand for rec.arts.sf.fandom, the Usenet news group that is probably the closest net equivalent to general fandom which is not invitational and/or is not focused on being primarily just that. Simply put: A lot of old-time fanzine and convention fans and former fanzine and convention fans tended to hang out there.

The group was very important in the 1990s, and could have been said to have been a focal point of fandom during that decade, however changing technologies, the appearance of new social media, and greatly increased interpersonal friction over politics, post-9/11 contributed to participant attrition so that by the mid 2000s, many of the fans (and much of the action) had migrated largely to Live Journal, personal blogs, and other newer channels.

https://groups.google.com/forum/#!forum/rec.arts.sf.fandom (IA) rec.arts.sf.fandom archives on Google Groups