Startup career site taps Facebook social and professional graphs of those too cool for LinkedIn.

When I spoke with Brendan Wallace, co-founder and CEO of the startup professional networking site Identified, I doubt he was trying to make me feel old and depressed. I'm probably being oversensitive. Old people are like that, I guess.

Identified is a search tool for recruiters based on the Facebook social graph. Why not the LinkedIn professional graph? Because LinkedIn is for old people, not young professionals, fresh from good schools, who have their whole lives ahead of them.

"Most people in their 20s are not creating profiles on LinkedIn," Wallace said. "If you look at people under the age of 35, Facebook has 130 to 140 million. That demographic on LinkedIn is about 8 to 9 million. Younger people are using Facebook as their professional graph, whereas the people you know on LinkedIn tend to be older." He added that the average age of the membership on LinkedIn is 43 to 44 and "hasn't gotten any younger."

As an active LinkedIn user who left 44 behind a few years ago and isn't getting any younger, I couldn't help bristling at all this. I'm not saying Wallace is wrong, but it's no fun being old.

Meanwhile, I'm grouchy about my Identified score, which stands at 45. The score is a factor of work history, education, and professional contacts, and letting you see your own score is something Identified added when it announced its public beta this week. A score of 45 isn't horrible--I've been reassuring myself of that fact by browsing the profiles of friends and coworkers whose scores are lower--but Wallace, for example, is a 91. A 45 seems like a challenge to my claim to social media guruhood.

The score is simply a way of letting you know whether recruiters are searching for you, or someone like you, Wallace said. It's a numerical reputation of the ranking the Identified search engine uses internally, he said.

Wallace and co-founder Adeyemi Ajao are graduates of the Stanford Graduate School of Business and originally piloted the social search engine there as a tool for recruiters to find the most talented, best connected students. Before long, they had more resumes on file than the school career office, which actually forced them to shut the site down, Wallace said. Identified embarked on a plan to expand the service school by school before ultimately deciding to open it up more broadly. Can it be an accident that this sounds like a replay of the Facebook story?

Forbes writer Tomio Geron does a good job of covering the origin story in more detail.

Prior to this week, the Identified service was available in a fairly limited test to between 20,000 and 30,000 people, Wallace said. Now, it's growing by about 2 million people a day, Wallace said. One of the ways you can boost your Identified score is by inviting people to join the service, which they can connect to using their Facebook identities. Another is by fleshing out your professional profile with additional information on former employers, employment dates, college major, grade point average, and so on.

This highlights one of the ways Facebook is an imperfect match for recruiting and professional networking. Young people who can't be bothered with LinkedIn may record some of their professional information on Facebook, but because professional networking isn't the primary purpose of Facebook, that data is not necessarily complete.