What interests me the most about PSHB is the fact that I find myself *polling* several atom-based APIs on a very frequent basis. GData is probably the most salient of these APIs, but also Facebook, MySpace, Metacafe and several more.
Currently some of these APIs are kind enough to provide Expires headers which give me a rough outline of just how often I have to poll. Some of these APIs will let me HEAD first to see whether I should go ahead and re-fetch, but... I'm still polling!!! I don't want to poll. I really don't want to poll when there has been absolutely no change to the results of the API call (which is really just an Atom-based feed). To put things in perspective: the suits around here are deadset on tracking around 2 million videos and other entities (users, producers, etc) by the end of the month. Right now we have to poll several times per day for each video/user/producer. Considering the vast number of Atom-based APIs out there (I'm looking at you gdata), I'd really like to see APIs/feeds making more use of PSHB. I can't see how this wouldn't benefit both the maintainers of the API as well as the users. Our traffic to these external sites would drop an order of magnitude, and our data would be fresher. Maybe even realtime some day. A lot of what I'm consuming could immediately start using PSHB. Off the top of my head, Youtube's feeds for instance are ready to go, as well as metacafe. MySpace seems to be adopting PSHB already. I think if GData lead the way, literally everyone that matters would follow. Imagine being able to build applications on top of GData fed through PSHB. I can immediately see some usefulness with the Calendar API, Docs API, Finance API... And if the Youtube API went this route, I would start using it literally same day. Blogger seems like a given as well. It also seems to make sense that the company pushing PSHB might also adopt it...
