And honestly, even before that, there were a lot of spaces. HP fandom is actually a lot more restricted. There used to be tons of websites, the ff.n HP fic archives, Ao3, messageboards... insanity. The only difference is that it was more of a chain, for the most part - there were some more separate aspects, I always felt like The Leaky Cauldron and MuggleNet were almost their own fandoms within the fandom (this isn't a criticism, just an observation), whereas in a lot of ways LJ was almost the fandom's Facebook page. So if I had a response to a thread on a forum that was a bit OT and/or tl;dr, I posted it on LJ, and I added friends I met from there. I guess that sometimes happens with tumblr on LJ, but I feel like it can be pretty separate, too.