Has Facebook lost its cool? An increasing number of teenagers, apparently turned off by the graying of Mark Zuckerberg's 800-million+ user social network, are making the digital trek over to Twitter. Here's what you should know:

What's going on?
A newly released report from the Pew Internet & American Life Project found a "slow, but steady" increase in the number of teens using Twitter, says Martha Irvine for the Associated Press. Two years ago, just 8 percent of kids ages 12 to 17 were using Twitter. By last July, that number had doubled to 16 percent.

Why are teens flocking to Twitter?
"Teenagers like how easy Twitter is to use," says Emil Protalinski at ZDNet. They "like being able to send what they see as the equivalent of a text message to a smaller circle of friends, and they like being able to have multiple accounts on which they don't have to use their real names. Throw in being able to follow your favorite celebrities and Twitter is actually quite appealing."

Any other reasons?
The aging of Facebook. The increasing number of "parents, grandparents, aunts, uncles, neighbors, parents' friends, and anyone in-between" jumping on board Mark Zuckerberg's social network apparently makes Facebook less cool for youngins, says Protalinski at ZDNet. It's true, says Katherine Stone at Babble. With so many parents now "Facebook savvy," teens felt they "could no longer have a private conversation among friends."

Are teens actually shutting down their Facebook accounts?
No. Young people are just becoming more active in the Twittersphere, and a relatively small number are putting their Facebook accounts on the back burner. Of teens who are on just one social network, 89 percent pick Facebook, while less than 1 percent are using "just Twitter," notes Protalinski. Of teenagers who use more than one social network, 99 percent are still on Facebook.

Sources: Associated Press, Babble, ZDNet