I’ve been speculating on a new Web project, gathering information to help me decide if a standalone website is indeed the best vehicle for the new venture, or if it could run on top of Facebook either as a Facebook App or Facebook Page. In the course of my research, I came across a handy technique for exposing otherwise unpublished information about Facebook’s users. This little trick is probably well-known in some circles, but I haven’t seen it widely discussed, so here goes:

Like the Google Adwords traffic estimator, the Facebook Ad creation interface is designed to help advertisers target and scale their cost-per-click (CPC) campaigns. In doing so, it provides a number of targeting filters that generate estimates of the total number of Facebook users meeting given criteria.

Facebook Ad Creation Interface

“As Facebook’s enrollment grows to encompass effectively everyone and the company offers increasingly granular targeting filters, the estimator tool itself may become a useful tool of market and social sciences research.”

This data has obvious utility to advertisers. But as Facebook’s enrollment grows to encompass effectively everyone and the company offers increasingly granular targeting filters — as of mid-July, advertisers can target users on their birthday! — the estimator tool itself may become a useful tool of market and social sciences research.

No doubt the estimator can uncover anomalies that warrant further investigation. Consider this one: Of the almost 24 million 20-somethings on Facebook (10,980,540 men, 12,899,180 women), the men are more than 50% more likely to describe themselves as “single” than women (33.6% of men vs. 21.7% of women). Presumably, the difference lies not in the reality — there are not that many more single men than women — but in what information these two groups want to expose about themselves. Are these young women leery of online suitors? Are these young men leery of commitment? (Alright, it’s not the most rigorous or interesting example, but you get the idea.)

For my project, I was interested in Facebook’s penetration into U.S. audiences by year of birth, and so I whipped up the quick chart below comparing the data from the estimator to Census estimates.

Facebook's Audience by Birth Year

I’m looking forward to more creative uses of the Facebook Ad targeting tool as it grows and changes. And probably some incredibly ordinary CPC campaigns, as well.