At YourTrove, a lot of what we do involves ingesting social content via APIs and then regularizing that data within our system. For a lot of data, this is pretty straightforward. For example, while Facebook and Flickr might return different meta data, or name fields differently, no one disagrees that a photo is a photo. This is true for essentially all uploaded binary user generated content.
We've added 10 APIs to the ProgrammableWeb directory in Government, Environment, Gambling, and other categories. Also added were several libraries for use with the LinkedIn API.