The Stattleship Python SDK by Stattleship allows developers to integrate the Stattleship API into their Python applications. This SDK covers football, basketball, and hockey data with baseball coming soon.
The Twitter Streaming API has been successfully used by Yahoo!, Google, and Microsoft, who have been given access to the full feed of all public tweets. Twitter has now enabled this "firehouse" of data for a number of other companies.
Google Buzz is a new service that takes aim at Facebook and Twitter by providing the ability to post links, photos and status updates directly from your Gmail account. And right off the bat Google has released the accompanying API.
Defensio, the anti-spam service, offers an API that can be integrated into blogs and web sites to fight spam comments and other unwanted spam (details at our Defension API profile). The service appears to be run by a small team, and is similar in purpose to Akismet, the much larger spam filtering service from Automattic (which powers WordPress.com), who also offer an anti-spam API.