I just read about this startup: Aardvark.  I think it searches questions you ask through social networks to identify a likely expert, and then gets a answer/reply for you. Anyway started in late 2007.  Sold to Google for $50 million in Feb 2010.  Built in Ruby on Rails and their job posts show they are still hiring Rails programmers.

Why Rails is appealing to startup web services

A startup can go from idea to professional web-service very quickly in Ruby on Rails.  Changes can be added daily as the service grows because the code is so maintainable.  When traffic comes, Rails can be optimized to handle millions of hits.