Web service APIs not only have to work, but they must also appeal to developers' high expectations. It's not enough to expose their data; if you don't offer powerful functionality, provide clean documentation, and maintain reliable service, they'll invest their time elsewhere. On this panel, developers from leading web applications share their best practices for building developer-friendly web service APIs.
http://2008.sxsw.com/interactive/programming/panels_schedule/?action=show&id=IAP060350