Thanks Timothee,
This may just be a case of wording, we started as a bit.ly for iPhone apps, and moved into the services for iPhone developers. If bit.ly would offer a premium service where you use a subset of their URLs (say, bit.ly/app_XXX) and they put in affiliate codes so that they can track your sales data and give it back to you, people's reaction would be 'sweet, more features from bit.ly'.