In a study of 300 hiring managers and recruiters, Palo Alto-based social networking monitoring service Reppler reports that 76% of hiring managers look at applicants' Facebook profiles. An additional 56% are looking at Twitter, and 48% check out LinkedIn - which seems ironic, considering that LinkedIn is where you're supposed to present your professional self.

Facebook serves as an extension of your offline self, and employers want to know what kind of person they're thinking about hiring.

This trend dates as far back as 2006, when CareerBuilder.com surveyed 3,200 hiring managers and HR professionals about whether they used social media profiles to learn more about potential hires. The results showed that 22% of hiring managers checked social networks when looking for potential hires, up from 11% in 2006.