Facebook, Twitter, and social media are new tools in the online dating realm. While most solutions use Facebook or Twitter to do things like make it easier to sign in or populate their dating site with data, few really use the social graph to connect you with potential mates.
Thread is a tool that uses the Facebook social graph to help you find people to date based on friends of friends. After all, you're probably going to be more comfortable and more successful in your dating endeavor if you have a common link and a mutual friend.
The problem they intend to solve is that dating sites are inauthentic and risky - something that my friends in the dating industry actually tell me on a weekly basis. So Thread tries to fix this problem with authentic, rich profiles (based on your Facebook profile) and having friends vouch for you. Thread claims a higher success rate than most dating websites - something that probably isn't all that hard to do.
Signing up just requires connecting with Facebook Connect. Your Facebook info and friends then populate your profile so that you can either ask someone to introduce you or help play matchmaker. Want proof it works? One of the founders actually revealed that he is now on his third date with a woman he met on Thread. It's "practice what you preach" in action.