They are beating Google at their own game. I wouldn't be surprised if Google announced a real desktop OS, since they basically pulled the plug on Chrome OS and Android isn't even fit for Tablet.

Microsoft is basically trying to outgoogle Google, and they are trying to do that at the OS level, not at the browser level. From a purely strategic standpoint this is brillant. From a user stand point it's obnoxious of course, because good luck blocking ads if Microsoft decides Windows won't allow you to. Clearly web advertising is drying up, so Native ads,i.e. at the OS level is where the growth is.

EDIT: correction