For over a year developers have been asking for an API from Quora, the Q&A site that has recently exploded in popularity. The company had been waiting until there were "enough users and content on Quora." A browser extension outed the interface and now there is an officially released, but still alpha Quora API.
With the holiday weekend coming up in the U.S., avid divers may be making their way to their favorite spots. Dive.io is a web service designed for divers, so they can log their dives, share their favorite dive spots, and meet fellow divers. It's very specific, but it does its task quite well. It also has a nice API, allowing for integration of the service into, well, anything at all.