New Web2.0 site written on Rails and I have a gut feeling that they will actually get some decent popularity. For an example of what you can do with it, check out my Ruby on Rails search... http://rollyo.com/search.html?sid=3518&q=obie (Sorry about the egocentric query. :-/ Rollyo is AJAX-heavy and incredibly they lack a good URL scheme for accessing a particular search, without kicking off a query that is.)