When it comes to social networking, it seems everyone is obsessed with Facebook. The big meme du jour is that Facebook will soon surpass MySpace as the biggest social networking site on the Web. Frankly, I don't think this is an interesting question. Regardless of who wins this race, both sites have amazing growth numbers and don't seem poised for a downturn anytime soon. The more interesting question is this: Will Facebook kill LinkedIn to become the primary career networking site on the Web?When I look at Facebook, I see a social networking site perfectly designed to capture professionals from cradle to grave. Facebook's heavy emphasis on college students and do-gooders has given it a lock on the middle class and upwardly mobile demographics.

LinkedIn is a social networking site designed to capture the same demographic. But it faces two big limitations. It's not big with college students and given LinkedIn's stripped down format, it doesn't offer any multimedia or graphics to appeal to them.

Facebook has just the right amount of bling. It's not as overdone or kludgy as MySpace, but it has enough graphics and video for both college kids and 40-year-old professionals. And that's a killer combo.

Regardless of what you think of Danah Boyd's recent class analysis of the two social networking sites, she does get a thing or two right. Unless you're a musician or an artist of some kind, you don't use MySpace to advance your career. You probably use LinkedIn for business networking and, if my personal experience is any barometer, your LinkedIn connections are all rapidly going over to Facebook (and sending you invites along the way).

If you are a college student you probably use Facebook and there is a chance that you also use MySpace. But once you graduate, I suspect you'll stick with Facebook and ditch MySpace, especially once you settle into your first job.

And if you're a graduate student (especially in business school or law school), you probably use both Facebook and LinkedIn. And if the majority of your LinkedIn connections migrate over to Facebook, you will probably stop using LinkedIn at some point in the near future.

What do you think? Will Facebook kill LinkedIn? Will it become the primary social networking tool for professionals? Or is there a place at the table for both Facebook and LinkedIn?