CK has a great post about how so many of her marketing client type friends think they're "too old" for social media, even though chronologically they're still in their 30s.
And I find the same thing happen with my friends too, even the ones in the creative departments of ad agencies. When I tell them I have a blog or that I'm on Facebook, I often get razzed about whether I listen to Hannah Montana or hang out at skateboard parks. Implication being that I'm way too old to be involved in things like social media that are best left to "the kids." (NB: You'd also be surprised at how many of them still assume a "blog" is some sort of online diary, where I write down my deepest, most intimate thoughts for the world to read.)
Now these are normally intelligent, sophisticated people who, if I had to guess, feel very in control of the worlds they've created for themselves and don't want to put themselves in a situation where they're no longer in control and where they're afraid they're going to wind up seeming like the chaperones.
The truth, as anyone reading this probably knows, is pretty far from that. Blogs aren't all that different than magazines, Facebook and LinkedIn are pretty intuitive once you start playing around with them and posting on a message board isn't brain surgery. What's more, unless you're actually on a Hannah Montana or High School Musical site, the majority of your fellow social media contacts are going to be established professionals around your age who share everything from your musical tastes to your professional interests.
If you work in advertising or marketing, you should definitely be checking out as many new media vehicles as you have time for, as many Twitters and Pownces and Second Lives as your schedule allows. You don't have to be an active user but you do need to check it out enouh so that you can speak intelligently to it when it comes up with your clients. Don't forget too that someday all those kids are going to be your target audience and you're going to want to know how they think and how they operate.
You'll probably even wind up discovering why social media is so popular and why so many people spend so much time on it: It's kinda fun, once you get the hang of it.