I developed a mobile front end to StackOverflow... and I was wondering what category it fit under...
I mean, is it an app? Something else?
I think we need an additional category: services.
No we don't. It is an app.
Simplicity is key to keep clutter at a minimum. The current two categorizations are perfect:
An app is something you make that utilizes the API to do something.
A library is something that provides an abstraction between an app and the API.
No need to invent a bunch of categorizations that aren't necessary.