The idea is that developers can take Face.com's technology and apply photo tags for various purposes. Facebook users would essentially be able to tag images as they browse the web and personalize their experience on any website.
Face.com created three examples to show how the API can be used. The Tagger Widget shows the tagging interface for website photos, highlighting how users can click faces to add names. Poster Yourself is an example of how the API can be used to plug faces into posters and CelebrityFindr's mini site filters celebrity photos mentioned on Twitter.
Face.com is already responsible for tagging more than 50 million users, so by letting developers piggyback on its platform it will only create more value for users and continue to extend the service's reach across Facebook.
The API should prove promising for users, developers and Facebook. Users can personalize their photo experience on websites across the web, developers can build uses that appeal to Facebook's massive user base, and Facebook will serve as the fabric that helps connects the dots between faces and real people in photos.