A new Web site and smartphone app connect license plates with an e-mail address, allowing businesses to track customers, drivers to connect with each other, and road rage to reach new heights. In doing so, Bump.com, which launched this week, throws open the doors of one of this country’s last private places: Your car.

The site aims to bring social media connectivity to the road, even for cars that don’t come with Wi-Fi. “We’re right next to each other on the highway, but we have no way to communicate, connect, and network,” as Bump’s Web site explains.

It works by connecting a car’s license plate with a Bump user account, which can then be connected to other social media sites like Facebook and Twitter. You can add your physical address and mobile phone number, too. License plates become an e-mail address @bump.com.