I think we all saw this one coming. The hottest social aggregator out there today, FriendFeed, has launched an application programming interface, paving the way for third-party applications using its service. Full documentation for the API is available on Google Code.
This is certainly an important step for FriendFeed. The closely related service, Twitter, has benefited greatly from providing support for third-party developers, so FriendFeed should see a similar bump from the introduction of its API.