It's not obvious at all. They haven't cracked down on external software sources and I doubt they are stupid enough to believe they could get away with such a th

It's not obvious at all. They haven't cracked down on external software sources and I doubt they are stupid enough to believe they could get away with such a thing if they tried. It would be a dealbreaker for business users in particular. I think the more plausible explanation is that Microsoft wrote the store because users expect to have one on mobile devices (i.e. Surface) and Windows 8 was an attempt at tablet-PC convergence.