Twitter has a reputation as that "new Internet trend" that's all the rage among kids, but recent data suggests that an older crowd is what's really driving Twitter's growth. Sparked by a very unscientific Morgan Stanley report (PDF) about how teens apparently don't use Twitter, market research powerhouse Nielsen decided to take a look at its own data from a NetRatings panel of over 250,000 US Internet users. While "teens don't tweet" is a pretty gross generalization of the data, the young'uns don't make up as significant of a group as one might expect.

According to Nielsen's data, Twitter reached 10.7 percent of all active Internet users in 2009 "despite a lack of widespread adoption by children, teens, and young adults." The firm notes that people under the age of 25 make up almost a quarter of all US Internet users and yet only 16 percent of Twitter's audience in June of 2009, meaning that Twitter is "under-indexing" the youth market compared to the Internet as a whole. Conversely, the large majority of Twitter users (64 percent) fell into the 25 to 54 age group, and 20 percent were 55+. That's right: there were more Twitter users who are our parents' age than those who are in high school or college.

This isn't to say that kids aren't into Twitter—they're just not as into it as those who are over 25. As Nielsen points out, Twitter is largely driven by buzz (see Michael Jackson's effect on the service), not to mention the fact that numerous marketers, PR people, and journalists use Twitter to push their wares and build connections. Frankly, it's no surprise that mass numbers of younger folks wouldn't be as interested as older adults—who wants to hear about what's going on in Iran when you're texting interesting high school gossip around? (High school readers: that last sentence was tongue in cheek. Lay off the hatemail!)

Of course, this also doesn't take into account that most Twitter users don't tweet or even follow anyone, so this may be a case of adults joining to see what it's about and later deciding it's not for them.

Listing image by From Flickr user Wouter de Bruijn