Not sure why I didn’t look into this sooner. OData. Open Data Protocol.
Not many providers, but this has huge potential. First off, PowerPivot can consume OData feeds! See the “From Data Feeds” button :)
But, you can see how easy it is to create an OData API for your data? Scott Hanselman did it for StackOverlfow in 30 minutes. This opens up HUGE oppourtunities for apps and ISV’s to expose their data out for end user and other developer consumption.
You can see all the “producers” here: http://www.odata.org/producers .. I am sure there are more, just not on the list.
What a cool easy way to expose your data as an “API” out there.. Excited to see how it is used (Pivot Viewer, Power Pivot, etc) and what people do with it.