Teens Now Using Twitter More Than Facebook?

I think the new trend among teens is to use Twitter more than Facebook. At least, that is how it seems to me. I have a teenage relative who is now using Twitter all the time, in addition to just texting constantly. Apparently, Facebook is still being used by teens but has taken a backseat. What is the reason? I think they feel that adults are monitoring their facebook pages too much, and they have more anonymity with Twitter. Makes sense I guess. I may be harder to figure out their twitter username if they don't tie it into their real names or some other obvious nickname.