There are so many jobs listed for developers familiar with the Paypal API on GetAFreelancer that the site has a category dedicated to it. And that's not all--there are over 300 API-related listings on the site, which connects freelancers with people who need programmers and designers.
A few weeks ago we reported on the release of the Kiva API, which provides access to the Kiva.org global microlending database. Not long after the API's release, blog posts from Bill Zimmerman and the Kiva team report that several developers are already working on Kiva mashups:
How much will it cost to hire that cabbie? The Yourtaximeter API gives access to such precise data that cab companies in the UK rely on it to give quotes. Yourtaximeter provides a tool anyone can use to calculate a fare. The API documentation, other than providing a link to where you can get an access key and noting responses are flexibly delivered in JSON or XML, is rather skimpy. That's actually a complement: minimal documentation reflects the fact that no coding skills are required.