An emerging API for allowing external sites to request the embed code for snippets, widgets, gadgets, and other embeddable information/media for a site. I'm seeing it get some good uptake in the latest round of CMS tools and community platforms.
The Launchpad website lets you learn about and manage bugs, projects, questions, and other artifacts of software development. These same objects are gradually being exposed through a web service, so that you can access them from scripts, applications, or other websites, in addition to accessing them through the Launchpad website. The service is designed around the principles of REST, with the goals of simplicity and transparency.
The Launchpad web service is currently in a limited beta, open to Launchpad's beta testers.
I was totally unaware of this service, and the breadth and depth of it's capabilities, the possibilities are huge, I'm going to look at incorporating that into some of my pet projects as soon as I have a need.