First, no one has a "real" smartphone, most are cheap Nokia phones with some applications for Facebook: People who have money usually buy BlackBerries, I have a Samsung Galaxy Ace (Being an Android fan) that I bought in Spain: but truth is smartphones are really expensive.
Facebook... everything is about Facebook here: Teenagers don't use any other IM service besides Facebook Messenger, they even use it in their phones. I find it extremely painful to communicate because I need to keep a Facebook window tab opened if I want to chat with someone (Well, I use Pidgin now).
I don't even go into Facebook, the Facebook feed looks like browsing /r/funny New in Reddit, people don't post original content: Just memes copied from the internet and cristian stuff.
People tend to have a lot of friends in Facebook: I think I don't have more than 50 friends: Those who I really would like to talk with me and have access to my pictures.
What people really use here is ask.fm , I'm not sure if people in other countries use it: but the basic idea is that you create an account and people (Logged, or as Anonymous) post you questions and you answer: Then it gets posted in your Facebook.
I don't understand why would anyone want to use that service: The questions are dumb and nosense. Other questions are personal, and some people still answer that. Nowadays most of my Facebook feed is 75% ask.fm links, it's really annoying.
Other services? Some people use Twitter, but not really; mostly teenagers following One Direction and Justin Bieber.
Blogging? Nah, no one reads blogs: they don't like reading anything larger than a couple lines of text (I think this: http://www.theatlantic.com/magazine/archive/1945/07/as-we-ma... can be relevant).
Youtube... they like dumb vlogs and some people like gameplays, I find this kind of videos very annoying and dumb.
Oh, not even mention Mail: most of people can't remember their passwords, for me, Mail is vital. Tumblr? No one knows what that is. Ah, no one uses Instagram either, and I'm glad...
So resuming: Teenagers only use the internet for Facebook, and, sometimes, reading the Wikipedia (When they have to do something for school) and that's really bad: They have a wonderful tool that they don't want to use, although the language (Most of teenagers don't have a good level of English, or at least they refuse to read English) can be an impediment.
For me the internet is amazing: you can learn whatever you want, for free, thanks to tools like Khan Academy, Coursera and Udacity: But people refuse to, and the language is not the only issue. I think we should focus our knowledge into motivating the Teenagers to get interested into this, instead of developing more applications like Poke or a Facetime killer.