One of the design philosophies that I like about PubSubHubbub is the decision to put as much of the complexity in the hub as possible, making it simple for feed publishers and readers to support the protocol. For this reason, when I created a Java application that receives updates, I was surprised when some fat pings arrived in RSS 2.0 format instead of Atom.
Is there a possibility that fat pings will be normalized to Atom, no matter what format the originating feed employs? If you normalize the pings, PuSH clients only have to support one feed format. If you don't, clients have to support Atom, RSS 0.9, RSS 0.91 (Netscape), RSS 0.91 (UserLand), RSS 0.92, RSS 1.0 and RSS 2.0. Although all current feed-reading applications must support all of those formats, if PuSH normalizes pings, it makes it possible for future applications to be developed that only have to support Atom. That would be a nice selling point for developers.
