Discussion of Google's recent acquisition of Jambool has largely centered around its virtual currency platform, Social Gold. The power behind that platform comes in the form of the Social Gold API. Again, Google has bought a company whose API is central to its success.
The humongous amount of data that Twitter generates daily, is spawning a new breed of company that is analyzing the data and providing value-added services on it. While the data mining and intelligence applications are still in their infancy, there are interesting applications that you can use today.