There have been a lot of facebook apps that have come and gone, and now there is Bitstrips. Bitstrips are personalized comics/cartoons that you can make of yourself alone or yourself and a friend.
It has a phone app available, and you must have a facebook account to log-in. The app says that non-facebook accounts will be supported soon, but they aren’t as of yet.
The way the program works is like this: you make an avatar that looks like you do, and then the program automatically populates a number of one-cell comics with captions with your avatar in it. A lot of the ones it populates include another person, and the caption will read, “Bitstrips is more fun with friends,” and it will give you the option to “Add a Costar” (a friend).