theyarecomingforyou wrote on Jul 26, 2012, 09:18:
Microsoft allows you to make in-app purchase externally to the Windows Store (app certification [4.7]); although it doesn't explicitly state so, that should avoid Microsoft taking a cut of the transaction (the same goes for ads). The trade-off is that the user is prompted every time an external transaction is made. However, if you are indeed correct - which is a distinct possibility - then that would have to be a breach of competition law, at least in the EU. Afterall, Microsoft is already being investigated by the EU for not allowing other browsers onto Windows RT. Otherwise it would be HUGELY destructive for the entire industry.

Like I had said on another forum, good luck getting MS to license out DirectX to have all of those titles run on Linux. Otherwise, the Devs would have to port the games and we all know how great ports are....