title: How to write backwards compatible HTML5?
body: <p>I'd like to start using HTML5's basic features, but at the same time, keep my code backwards compatible with older browsers (graceful degradation). For instance, I'd like to use the cool CSS3 properties for making rounded corners. Is there any available tutorial for writing gracefully degradable HTML5 ?</p>
  
  <p>Additionally, what browsers should I support so that my app. is functional for at least 95% of visitors? What are the ways to test those browsers painlessly ?</p>