[pavlov]

Windows Phone 7 had a genuinely unique twist on the unified inbox.

The operating system deprioritized apps with their own feeds, and instead provided a number of "hubs" that were like topical inboxes that collected data from multiple APIs.

There was a People hub that showed your contacts aggregated across phone contact book, Windows Live, Facebook, Gmail, Twitter... Notifications about people you know would show up in this screen regardless of the service. And there was a Photos hub that similarly showed photos from everywhere: local, Facebook, etc.

It was a truly original idea for a social media oriented phone. But companies like Facebook and Twitter were not too happy about the idea of being API pipes with little or no control over the user interface on the user's phone. Of course they had some good reasons not to trust Microsoft on this, given Microsoft's past behavior. I think FB shut down the necessary APIs completely a few years later and replaced them with more limited options.