Frequently, JavaScript-heavy applications are for individual use: think GMail, Basecamp, or Google Docs -- none of which need to be indexed by web crawlers.
But if you are doing something public facing, you can get it indexed by Google with a little elbow grease:
But if you are doing something public facing, you can get it indexed by Google with a little elbow grease:
http://code.google.com/web/ajaxcrawling/docs/getting-started...
"New Twitter" takes this approach.