So AtomPub is a reasonable way to publish things, etc. Would be nice to push an AtomPub endpoint to a service as a callback for events. An awfully large number of things can accept HTTP now, and there is a reasonable basic-operation system available, so why not take advantage for callback APIs? Instead of polling a site for updates, post a subscription with an AtomPub endpoint as the entry and let the service push to you. AtomSub :-)