Backgrounder
The badges are indeed from Backgrounder, which is an "app" or a "package," available through Cydia and Icy on jailbroken devices, which adds code to selected applications (like Pandora, Last.fm, or any other app store or jailbreak app) to keep them running in the background after you've pressed the home button. To turn backgrounding on or off you launch/open the desired app and hold down the home button for a few seconds.
The badges can be removed in the Backgrounder preferences. They show you which app has a process running in the background so that you don't exhaust your RAM by backgrounding too many apps because you forgot you had something else backgrounded.