Instagram! Great site, and I just joined a while ago! You can follow your friends and like their picture.
Pinterest! Love the site because I have worked up to 3.3k at this moment at Thursday, November 12th at 7:23pm. I  pre wrote my book!
Tumblr! It eats your soul! It's great, but not one of my favorites.
Facebook! It's okay, but I like other sites, too.
Twitter! It's good for writers for TV and books. It's awesome for spoilers too.
Google+! It's okay, but I really don't use it.
Flickr! I really don't use it, but I have heard that's it's great!
YouTube! I use this daily, and it's awesome! Make videos and post them for people to watch. Yes you may get criticized, but it's worth it!