At Google I/O, Larry Page, Google's CEO, came to the stage to talk and take questions, and he got a chance to say that Microsoft is "milking off" Google's innovation. He was referring to the fact that recently Microsoft took Gtalk contacts and integrated them into Outlook, but they aren't (freely) allowing the same thing to happen with Skype contacts.
This can happen because Google uses an open protocol called XMPP for Gtalk, while Microsoft is using Skype's own proprietary and closed protocol. This is sort of a "no good deed goes unpunished" situation, because Microsoft can take full advantage of it, with it being open and all, without having to give anything back to Google.
Larry Page seemed very upset about this, and I think the response to this will just make it worse for everyone. When Facebook did a very similar thing with Gmail contacts, by leeching them off, and then not giving any data back to Google, Google responded closing the Gmail API for everyone, so no one can use Gmail contacts except Google, in their apps.
I predict Google will be doing the same thing here, and rumors are that the new Hangouts app, which will replace Gtalk on Android and on the desktop, will remove the XMPP protocol, and will use its own proprietary protocol instead. It's really unfortunate that it has come to this, and I wish the situation would be better, but at the same time I kind of understand Google's position.
Google doesn't like it that other platforms are growing off their backs, and then even competing with them, instead of collaborating with each other to create a much larger open ecosystem for everyone. But it doesn't look like any of the big companies is interested in doing that right now – not Apple, not Microsoft, not Facebook, not Amazon, and increasingly more often lately, Google doesn't seem interested in it anymore, either.
Everyone wants its own walled garden of some sort, and its own ecosystem, and they want users to join their ecosystem fully. I'm not sure how well that will work for them, as people use different services, and they don't choose their friends based on the companies they love. The next few years especially should be pretty chaotic from this point of view until things settle down.