Google Groups basically destroyed all Usenet competitors and now is going belly up itself, likely taking down a large portion of computing history with itself.
Usenet was generally pretty good at sticking to binaries for the warez and copyright content. Hosting the text-only groups was not that intensive, especially by today's standards. I think the worst problem was sites that just didn't care... I spent a day reporting spam posts to the admins of origin servers, and they just didn't care at all.
Today, it's far less of an issue.. but if Usenet got popular again, the spammers would get back into it. I can only imagine how much spam gets removed/filtered on this site.
