In an ideal world, there'd be no need for the patterns to be presented here. But in practice, the only way to produce truly rich applications is to push the boundaries of standard web technologies. This  presentation will flesh out the Ajax edge cases - what we can and can't do, should and shouldn't do. For example, can an Ajax application make URLs bookmarkable? Use encryption? Include sound effects? Based on real-world examples, the talk will describe how people are using standard web technologies in ways that had previously been considered impractical, and highlight browser trends that are opening up new frontiers. And where applications do have to extend beyond those standards and invoke technologies like Flash, the presentation will explain how such extensions can be integrated as seamlessly as possible within an overall Ajax application.