David Heinemeier Hansson writes about Ruby on Rails as “disruptive technology”
“…Rails is able to deliver incredible improvements for the majority of projects that are currently being over-served by J2EE/.NET by sacrificing a whole herd of golden calves. The sacrifices are condemned by the high priest exactly because of their status as high priests, which means they work on the most complex projects and hence cast all decisions on technology in that context. Would this work for the 5% most difficult projects? If not, then it “doesn't scale.”
The pieces linked to from his post are worth a read also.