It will be very interesting to see what XNA support is like on the final model. There's a strong community of developers accessing these tools for free, which would allow Microsoft to roll out a full and lively app store quickly. I would be highly optimistic about Microsoft's ability to run an app store service, based on experiences with Xbox Live, Xbox Indie Games, and Rock Band Network. Since they're building from scratch, they could analyze and avoid legacy issues present in Apple's iTunes App Store ecology.<p>Converse to their potential strengths at running an app store, Microsoft has a difficult decision posed by marketing. There are a lot of people out there addicted to Xbox Live Achievement points. If MS allows you to earn achievement points via games on it's new mobile phone, it will get a <i>tremendous</i> boost in market share.<p>The risk present here is that the achievement points system requires additional overhead and review by MS, in order to prevent system breaking games. There's no feasible way for them to populate their app store with indies <i>and</i> approve achievement points for all of them.<p>In order to have their cake and eat it to, MS needs to be able to differentiate achievement point games from indie games, but without turning indie games into an unshopped ghetto (see Xbox Indie Games). My best resolution would be to offer a small differentiation to icons on the store, specifically take those icons for games with points and apply a smaller logo to the corner, much like on a shortcut icon. Perhaps make it a little gold medal with a green ribbon falling in an X shape ;)