Over the weekend I wrote the MSN Spaces photo album browser page which displays slideshows of all the photos in the various albums on a particular user's MSN Spaces space. This page also can display the photos on a randomly selected space. This webpage is entirely powered by RSS. The photos are obtained from the RSS feed for the Space and the list of random spaces is obtained by querying MSN search with the query 'site:spaces.msn.com photo album' and requesting the results as RSS. In fact, the information from the MSN Spaces RSS feeds is enough to build something like the Flickr related tags browser, where instead of showing related tags one could show spaces related to the user from the information in their blog roll which happens to also be provided in the RSS feed. Pretty nifty and all without requiring building a REST, SOAP or XML-RPC API.
I think he's missing the point about Web-style apps when he says "without requiring building a REST [...] API". Because the API was uniform with the rest of the Web and not custom to the service, it was an easy integration task - not a full project, just a simple development task. He's mis-directing people by shining the light on RSS when the real reason this works is uniform interfaces, resource identifiers and nice representations in XML.