The IM Generation?

CNN has an article today comparing baby boomers and generation (whatever the teens now are) on the topic of IM: http://www.cnn.com/2006/TECH/ptech/12/08/im.poll.ap/index.html

They, rather convienently, left out all the ages in between.

I read it and just wondered how much of the "youth IM" is really about being a teenager. I talk much, much less on the phone now than I did when I was 19. I email less. I write less. I certainly chat online less. Is it really that an entire generation will IM forever, or is it just that they are teenagers doing what teenagers do?