Last week, I did a piece on GISuser.com about the release of the new Acetate feature on GeoCommons. GeoCommons is an implementation of FortiusOne’s GeoIQ platform, which is exposed to developers via a RESTful API.
A couple of weeks ago, FortiusOne set up a Google Group for discussions about the GeoIQ API. If you are using the API, or are merely interested in it, this is something you may want to check out.