IMO this is part of why Facebook's user base is so resilient. From what I see, younger people experiment more, looking for something that fits their identity, what their friends use, what's new, etc. They also have more time and incentive to explore new apps. By younger people I mean teenagers, high-school and younger.

Older people, it seems to me, are more utilitarian. By older people I mean college and up. They use Facebook for events, or because the social world is harder to navigate in college/later in life than when you're in high school and your friends are neighbors or classmates.

Perhaps this is just my experience, or maybe I'm just very off on how I read this, but it's a thought. I don't think Facebook is trying to be interesting— I think they're just shooting for useful and "sticky".