Facebook is the category-killing social network, makes up a quarter of the earth's Web traffic, and can claim nearly three-quarters of a billion users. But many of them don't dig beneath the skin of what the social network can do. There's a ton of hidden Facebook functionality, most of which the average user will never find. PCMag readers, however, want to go deeper.

Facebook has come a long way since its dorm-room beginnings as portrayed in the fictional hit movie, The Social Network. Along the way, the site has beefed up its messaging, added more photo and video capability, and changed the way groups work. They've also taken some hits along the way, most often for privacy concerns. The latest of these is the sites new use of face-detection to identify people in photos for tagging. We've offered tips in the past for how to protect yourself while using the social network. And we've offered tips on safe social networking in general (in the wake of a local congressman's indiscretions). We've shown you how to use Facebook Places, we've even shown you how you can get the best local deals on mobile Facebook.

This time, we wanted to simply uncover some of the lesser-known fun stuff on Facebook to enhance your interactions. We cover everything from messaging to movies, with some other nifty interface and community features along the way. Read our slideshow to find out Ten cool things you might not know how to do in Facebook. None of them are earth-shattering, but if you spend as much time on Facebook as the average person does, even a little extra knowledge can go a long way.