question for fandom

This is not entirely out of only curiosity, but in the wake of LJ dying its ongoing slow death, the rise of tumblr & instagram, the spammy desert of delicious, and the domination of pinterest, where does fandom mostly reside, now? Outside of behemoths like fanfiction.net and deviantart, there doesn't seem to be a central gathering place (application/site) for major active communities. Or is there, and I'm just not seeing/hearing about it?

Considering that once upon a time, one could post images, fic, vids, and whatnot to LJ, on one's own journal as well as on a community journal, is there any one place that handles all the fannish activity, now? Or is it all truly broken into pieces?