The last time I checked, 50-somethings were the fastest growing demographic on Facebook. We all know which generation adopted Facebook first.Linkedin

Millennials love to poke fun at Baby Boomers for being late to the game. But the truth of the matter is that many college students and other "Gen Y'ers" have been late to dance on adapting LinkedIn. And in professional circles, LinkedIn is often considered to be the premier site for business networking, job leads, and information sharing. There are many good reasons for this: where else can you find a question & answer forum, a searchable database of companies and people, and identify your relationships within three degrees?

As of September 2008, the median LinkedIn user was 41 with an household income of $109K. Not bad.

Since that time, LinkedIn has grown exponentially--and they've also made a great strategic decision: they hired my friend Lindsey Pollak, author of College to Career, to partner with them in growing their presence on campus.

I sat in on a webinar Lindsey ran for Career Services professionals last week, and got the latest stats on LinkedIn: The site now has approximately 45 million members, and is adding another million users every two weeks or so. Each second, a new member joins LinkedIn.

Are you LinkedIn? If not, consider it. And if you're a recent graduate, take a look at LinkedIn's 2009 grad guide, and see their special "networking offer."