To me wikis are probably not used too often by teens other than inside of classroom settings and perhaps to edit a few of their interests on wikipedia. Wikis generally are a little bit dorkier and solitary than the other tools we've been discussing. It involves understanding and creating code and also delving behind the scenes in the case of wikipedia and feeling a bit like a "know-it-all" or at least that you know more than the people who wrote the page.
It's a very empowering tool, you can see other people's typos and fix them you can research something more completely than another and have instant gratification. They are great for connect as well as we've seen through class and i still go to this blog by first going to the wiki to click the link i posted. Basically wikis are a great way to have a group of minds come together and combine.
Teens or young children, I guess I don't see them using a wiki as often as they possibly could be, this may be a bias in my mind, but it seems more like something you would do in college when your bored and beyond that point to be a bit of an intellectual show-off. Perhaps someone will prove me wrong. When I think of wikis I subscribe to the TED conference video podcasts and this one was very enlightening about the mindset and world of wikipedia.