Roleplaying in AOL chatrooms. I remember joining this group who roleplayed as vampires and hanging out in the "local tavern." I was only 9 and in hindsight half of what people were doing was hooking up, but it made me love writing.

Later on, I really enjoyed LiveJournal and staying up way too late reading fanfiction with my friends on AIM/MSN messenger.

Early Google. When AskJeeves fizzled away but SEO and ads hadn't taken over.