I don't see how the api key requirement will push devs away. If you have a simple ways to demo the api, like Facebook, Foursquare and YouTube all do, then it's

I don't see how the api key requirement will push devs away. If you have a simple ways to demo the api, like Facebook, Foursquare and YouTube all do, then it's easy to see the output you'll get. Assuming that happens, a key for tracking and preventing (serious) abuse seems necessary. Much harder to add security later as you'll break the apps from original ecosystem members.