Thanks. I guess that is probably the case.
I develop Windows applications myself and have my share of cracks. I guess the good thing is that there are probably more honest people around so that makes up for it. Those who strives on cracks probably may not pay for it no matter what you do.
I am not familiar with how the Android market does the licensing. I know for the iOS, Apple would tag a certificate to the downloaded bundle which I could use to validate the purchase.
What does Android do when someone buys the app from the Android Marketplace ? You were saying about authenticating with my own server, does that mean that as a developer, you would know who actually buys your apps ? Cos like in the Apple App Store, you only know the number but you have no clue who buys.