PubSubHubbub. Say that three times fast. If you're not familiar with PubSubHubbub, it's an extension of the RSS and Atom protocol that allows the feed to push content out when it's updated. That's just the sort of technology we should see from check-in APIs like Foursquare and Gowalla.
In 2011, the Guardian launched its local messaging bulletin: n0tice. Although the platform encouraged open journalism, the Guardian has expanded the effort with the launch the n0tice API last week. The very premise of n0tice offers value from a locality perspective. With the open API, the value of the local bulletin can be integrated with any developer's application.
We've added 2 APIs to the ProgrammableWeb directory today. Here's a summary of the new APIs as well as a recap of several recently added client libraries.