• by Erik Sass , Staff Writer, September 15, 2010

The only thing you really need to create an online social network is a group of people willing to share some aspect of their identity online. There are endless variations on this theme; why, there are even online social networks tied to credit card numbers, like Blippy and Swipely, which update your friends on your latest purchases. Next to these services, a social network based on your license plate number seems perfectly safe, if not positively cautious.

That's the idea behind Bump.com, a new social network which lets members create profiles tied to their license plate numbers and communicate with other members via their license plate numbers. Basically, Bump.com is like a location-based social network for car owners, documenting your movements and showing as much identifying information as you choose to share.

It also lets you send messages to other drivers without having to roll down your window and shout yourself hoarse -- instantly, if you happen to own a smartphone. A couple obvious uses spring to mind: you can flip someone the virtual bird for bad driving, or flirt playfully -- or both, if they happen to be reckless and hot. More usefully, you can tell someone their car alarm is going off, their taillight is busted, they left their lights on, or maybe make an offer for their sweet ride.

Bump.com has some neat built-in safety features: for example, if your iPhone's accelerometer (did you know iPhones had accelerometers?) senses that you are driving over five miles per hour, it locks down to prevent you sending text messages, and you can input other drivers' license plate numbers and dictate a message through a voice interface.

As far as security, you can choose to share your name and other personal information, or not; meanwhile, according to existing laws, state DMVs won't share the names of drivers with other people based on license plate number alones. Bump.com also said it won't share negative information about members (like bad driving practices) with insurance companies, although it will comply with information requests from law enforcement.