Unfortunately, I don't actually think an acquisition like this will pan out for anyone -- neither Microsoft, nor the customers. Mind you, my commentary is purely armchair speculation, but I really can't see how this will put Microsoft on any positive track. Without a doubt, after attaining Yahoo/AOL, everything will receive some sort of (unnecessary) overhaul to better integrate it with their business. This could, in turn, anger a hell of a lot of users of services that Yahoo provides. As well, I can see AOL disappearing into MSN, and Yahoo being refocused and shrunk to merely a marketing sector of Microsoft. Everything else will either be discarded, sold off, or overhauled on a massive scale.
Perhaps I'm completely wrong about everything, but I don't like the direction this is going. Also, this is all very speculative to begin with, since it relies on a very significant sequence of events.