Well, remember that they also do the hardware stuff in the form of the Xbox, as well as the Surface. They had the well-made Zune devices as well, even if they didn't perform well in the sales department.
As for what this means, I think it's something where they are actually trying to at least SOMEWHAT be ahead of the curve. Microsoft failed to do this with the smartphone market, as well as the tablet market. They're maybe seeing that the gaming market thrives online (mostly via Steam), and they probably like what they're seeing with Skulls of the Shogun. I think it's simply a matter where they are finally starting to look FORWARD with their products, rather than just playing catch up. I'm hoping this means we'll see things like we do between the PS3 and the Vita, where you have something like The Show. In that game, you can take your franchise or Road to the Show saves from your PS3 onto the Vita and play them on the go.
Ideally, this would end up like Skulls of the Shogun but without the massive buy-in (to get the game on your Windows Phone, Windows 8 computer, Windows RT tablet, and Windows Phone would cost $36, which is rather steep). I think one way they could get this started in the short-term is to start putting their Xbox LIVE Arcade games into these cloud services, then let those of us who own the XBLA games play them on our Windows Phones. For instance, I own Galaga, Paperboy, Uno, Frogger, Street Fighter II, Undertow, Carcassone, and a bunch of other XBLA games on my Xbox 360. They should get these working in the cloud and let me access them on my Windows Phone, without buying the games a second time. Some of these games (I'm thinking Galaga and Street Fighter) might not play well with a phone, but Uno and Carcassone are both on the platform now, I think. Not making me buy into the same game a second time would be a big thing for customers. It would probably make Windows Phone MUCH more appealing to the Xbox user base.