Jon Udell has a great article in the latest issue of InfoWorld discussing how Amazon's OpenSearch API uses RSS 2.0 for data integration.
Most people nowadays use RSS for person-to-person communication. You know the pattern: When a publisher posts a blog item, subscribers are alerted. A growing number of folks are also using RSS for process-to-person communication. Subscribing to searches is the best example of this pattern.
A9’s use of RSS for process-to-process communication represents a third pattern. We’ll be seeing a lot more of it. Not because RSS enables process integration in special ways -- it doesn’t -- but rather because RSS helps us blur the boundaries between human network and process networks.
As I've said in the past, RSS is just a delivery mechanism.