So, Google is not satisfied with the way paid apps are performing (not well) in the Android Market.
One of the ways is going to try to help developers make money is to provide in-app purchases. This makes sense and could help but is not the main problem. Carrier billing is an interesting approach Google is trying (with AT&T at the moment) to make app purchases simpler. However, it will also create a different customer experience depending on which carrier is involved. Google is also aiming at improving app discovery. However, Google needs to fix more than the app discovery process. The Android Market needs to be exposed beyond the platform itself. It needs to be visible in its entirety in either a web page or an iTunes like app.