Is it REST?

In the last Northeast Roadshow series, we spent a great deal of time discussing what makes a service RESTful.  As I indicated, I'm planning to follow up next time with a more hands-on treatment of the topic applied in .NET - including the newly released WCF REST Starter Kit and ADO.NET Data Services.

Anyway, as I was poking around today, I ran across a post on Roy Fielding's blog... remember him, the 'father of REST?'  In his post, he exhibits a bit of frustration with

...the number of people calling any HTTP-based interface a REST API.

Now I didn't look at the specific API that prompted his post, but I had to smile to myself that (hopefully) many of you that went to the Roadshow would be equipped to make a similar critical evaluation.  As in many cases, the comments to the article are as illuminating as the content.   Just a word of caution here, the conversation does stay in the ether a bit; Roy has a bit to say on that as well :)