Remember when Windows Phone 7 was going to clear out all the smartphone cruft and just help you communicate? Of course you do, because that's been the marketing campaign all along. Nevertheless, that's the pitch for the smartphone OS's major "Mango" update, which was previewed today (no word on actual arrival date beyond "fall"). There will be 500 new features, which the company "didn't have time" to cover, but they emphasized that the new OS will not only keep the deep Facebook integration it already had, but add LinkedIn and Twitter as well, which seems smart. Third-party apps have been "freed from their silos" and will be "part of the total experience". Care to speculate recklessly what that means in the comments? You've got several months to do so!