[jaakl]

Sure, I'm daily OpenStreetMapper myself. The other map options can be added in project basis, as the geodata from any other sources tends to be extremely expensive for average end-user app developers. Of course it has to be attributed properly in each app.

[TazeTSchnitzel]

Still, you should mention it (prominently, hopefully) on your homepage.

I don't think it'd hurt your business, quite the opposite. For some people, knowing it's OSM-based may be a feature.