It's a reboot of XML-RPC and the site that documents it.
The XML-RPC protocol was designed in 1998, by four people. Don Box, Mohsen Agsen, Bob Atkinson and myself. The first three guys worked at Microsoft. I was at UserLand. It became popular because it was so simple, and early. There were implementations in every major language and environment. For example, it was built into Python and the Macintosh OS. The main blogging APIs were done in XML-RPC. There is an O'Reilly book on XML-RPC.
It's been 20 years! We can do another new version in 2038, Murphy-willing, if we're still here, etc. This may eventually become the XML-RPC home page. It's not as beautiful as the original, but the links will be current.