Facebook was once known to be the place for college kids to see and be seen by their school peers. Since opening their doors to non-students, the growing social networking site has recently grown up to become a hit for professionals of all generations.

In June, 11.5 million of the individual visitors to the site were 35 or older, more than double the number a year before, according to market researcher comScore Media Metrix. The 35-and-up crowd now accounts for more than 41 percent of all Facebook visitors reports BusinessWeek.

The increase of household income of the users (48 percent of users have an income of $75,000 or more) has sparked the attention of advertisers looking to reach users on the site. Coca-Cola and Proctor & Gamble are planning to launch campaigns as early as this fall.

Dan'l Lewin, a corporate vice president at Microsoft, discussed how the company would help Facebook use its abundance of targeting data to help advertisers reach desirable consumers, "They may very well be building one of the next interesting collaborative platforms, and it may have business applications as well…they're learning in real time, and the audience is speaking."