Facebook announced a short while ago that they're rolling out a utility that brings true usefulness to their messaging function. They're going to allow users of Facebook the ability to search through past inbox [img src="http://sale-online.click/wp-content/uploads/2008/06/inbox_search.jpg" caption="" credit="" alt=""]messages.
Ever had a friend send you a Facebook message suggesting a good restaurant? Or maybe you were sent an address or phone number of an old friend. Then time passes and your Inbox fills up, and by the time you're ready to go out to eat with your old friend you have to page through hundreds of Facebook messages to find the one you need. Inbox Search aims to fix this problem.
In terms of additional features that improve the service directly available to the user (as opposed to developers or advertisers), its been a while since something caught my eye as something that would make me want to look at the service as anything other than a black hole for time and a place to get turned into a zombie (or a pirate).