Well, the next time you, your girlfriend, daughter, mom, dad etc writes a web service, perhaps they'll get some leverage out of it
:-)
(One interesting demo, not linked on the site but present in the source code on github, is a PubSubHubBub endpoint in the browser, which can subscribe to PubSubHubBub's feed update notifications for real-time feed tracking. (PSHB deliberately doesn't include any long-polling ad-hockery, so this is otherwise not possible.) The URL of the page is subscribed to the PSHB hub, and when new atom entries arrive, they're POSTed directly to the page -- or rather, as direct as possible given that there's the reversehttp gateway relaying the POST on.)