Chart APIs are useful and popular, and Google knows how to do them well, so they're continuously adding more features and options for customization to their Visualization API. The Google Code Blog recently highlighted a few of the newest features.
The legendary Billboard charts are now open for mixing, not by DJs, but by programmers. Billboard, a service of Nielsen Business Media, has a new API that lets developers search and read information from all the Billboard historical charts. The initial offering is its Chart service and later on Billboard will "roll out the Artist and Track services to add even more depth and perspective." the API is a simple REST interface that developers can send HTTP GET requests to in a familiar service/version/resource fashion. We've added a new Billboard API profile with details.
Gliffy, a browser-based diagramming and flowchart tool, today announced the public availability of their new API (technical details at our Gliffy API Profile). The four year old company announced the new API on its blog, noting that Gliffy hopes to take advantage of the growing trend of companies that are unlocking their APIs to extend the reach of their applications and data.