JGE Automatic Content Generator is a PHP script that will automatically add relevant content to existing web pages. Uses Calais to perform semantic analysis of an existing page's content to find essential keywords and then pull content relevant to these keywords from Freebase.
Rumblefish, champion of what is good and just and legally musical, will help you change your tune for the better. This company has produced a music licensing API so that you can add copyrighted songs to your YouTube videos. Of course the concept can be applied more widely and liberally. Rumblefish has even devised custom license ‘portals’ that present licensing options based on the intended use of the music. This implies that the agreement and cost of licensing a track could be more expensive depending on where and how it is used.
For the developer seeking to experiment efficiently with social APIs, O'Reilly's 2nd Edition of "Mining the Social Web" is a truly outstanding resource.
Author Matthew A. Russell drops the developer right into the sandbox of each social network (Twitter, Facebook, LinkedIn and Google+ are particularly emphasized, as you would expect) with just the right amount of explanation about what's accessible via each dataset, and then clears out all the obstacles so they can start data mining against very clear examples.