Nothing collaborative going here, just coincidence. Flickr has revamped their API a bit to deal with 3rd party Flickr apps needing authentication. In essence, Flickr will hand out time limited tokens to the app instead of the app asking for user's login/password combo.
Meanwhile, FeedBurner has launched an Awareness API. FeedBurner provides a level of indirection on webfeeds, which allows them to do readership calculations among other things. You proxy delivery of your webfeed and they give you interesting stats. The Awareness API lets folks get at their data through web services, so further applications can be developed.
My guess is that for any individual feed this is pretty boring, but for decentralized networks of sites this could be pretty important. FeedBurner could turn into the Audit Bureau of Circulations for webfeeds! Of course ABC is a relatively transparent non-profit and FeedBurner is a privately held company so there's a bit of a difference.