Simon Willison’s Weblog

YQL opens up 3rd-party web service table definitions to developers. This really is astonishingly clever: you can create an XML file telling Yahoo!’s YQL service how to map an arbitrary API to YQL tables, then make SQL-style queries against it (including joins against other APIs). Another neat trick: doing a SQL “in” query causes API requests to be run in parallel and recombined before being returned to you.