Joseph Schmitt, writing in response to Greg Pierce's hack to simulate x-callback-url support in Chrome:
However, Greg's technique depends on loading a full-screen iframe on the page and overlaying a back button on top to trigger the x-success url. That gets the job done, but I really prefer how Chrome handles this: make the last page jump to the previous app. I brainstormed for a bit and figured I could probably replicate Chrome's behavior's using Greg's idea, and I was right: xsuc.es was born.
To build actions with xsuc.es, see the URL parameters in Joseph's blog post. The format is easy to understand if you're already familiar with URL schemes; here's a demo action to launch a Google search in Safari based on xsuc.es from Launch Center Pro.