Uhm, TBT and a bit Youtube, mostly for watching videos and comment there.
I'm actually against twitter, facebook, whatsapp...
I rather like to use e-mails or the telephone. If it's my rival, we also communicate through writing letters through AION [game] XD
Youtube- to watch. My old account was for socializing and making acww videos.
TBT- my main
Google+ - I don't use that too often
I used to have a fb but deleted it and I refuse to make another... I used to have a twitter but I think someone hacked it o.o I ended up deleting that too,
TBT, Facebook (never use anymore ), Instagram, Twitter (no longer in use), Google Plus (Seriously who uses that?!), Youtube, Tumblr, Pinterest, and many more
Twitter, Tumblr, Snapchat, this forum, Instagram, Facebook, Youtube, Livejournal, FF.net, Google+, Blogspot, DeviantArt, Soundcloud, and other forums. I'm thinking about deleting or deactivating some of the accounts though. I don't really like Facebook and use it to keep in contact with family and friends while I use DeviantArt, Vine, and Livejournal rarely though.
I mainly use Tumblr. I have a Twitter that I actually use as an image hosting site for things I upload from my 3DS... But I tend to just take those pictures and post them right to Tumblr.
Too lazy to check whether I've already posted in this thread or not
Tumblr - but I'm taking a little self-imposed break until that friggin dress post stops making the rounds oh my god
Flight Rising forums - I'm not an active poster but I do lurk somewhat often I guess? Often enough for it to count, maybe, idk.
TBT Forums - I'm here so often it's embarrassing.
Youtube only when I'm looking for something specific. I don't like falling into that trap of clicking from one video to the next endlessly so I stay away unless I know what I'm trying to find.
No Facebook anymore (though I might sign back up just to get in touch with friends whose skypes/aims/whatevers have gone inactive or have been lost) and I never use my twitter, to the point where I only remember my username; I think I only signed up so I could watch certain companies for flash sale codes or something. I don't have a phone, but rather a tablet (which I use as a glorified alarm clock OTL - I would use it more if it was one I could draw on effectively like my partner's Samsung something-or-other, but mine is an old discontinued model wrapped up in an otterbox and it's not very responsive) so no snapchat or instagram or anything like that for me.
Actively? Tumblr and youtube. Although, I don't get very "into" youtube as in like subscribing to channels and commenting and all that. I just use it to listen to music and watch music videos. I really like tumblr.
I was also really into cosplay.com for a while. I really liked the forums there and seeing all the pictures of different people cosplaying.
I have most every social media out there, other than reddit and a few other things like that, I only use reddit for ACNL stuff. I don't really use my facebook much, other than to post things that I want my family to see, like a good grade or something-since most of my family is added on my facebook, which is both a blessing and a curse. And twitter i only use to complain or to tweet things as a diary type thing.