The SkyBiometry Python SDK by Tomaž Muraus allows API interaction to access recognition data. Example available demonstrates how to create a private namespace and recognize Guido Van Rossum, the author of Python language.
Czech-based eyedea Recognition has released a face detection API. It joins a list of some 38 in our API directory related to face detection. It's hard to tell how these offerings will stand out from the crowd. (By way of comparison, last October I wrote up Skybiometry.) Once the identity, gender, approximate age, and the ability to count the number of people in a room have been nailed, what else is there?