I've not see Economist Debates before but it looks to be a very well thought out environment for debate. They roleplay the form of a debate so well that it inspires courteousness from the general audience. The timetable and structure of the debate as well as the expert commentary is all very nice.

I'd like to see such a system for political discourse. At the local, state, and national level, it would be a welcome place to share ideas. If all the major news organizations are going to keep spewing opinionated journalism, we may as well take it to the logical conclusion. With opinion should come debate.