How to generate debate?

The Economist Debates - http://www.economist.com/debate/overview/209

I've been doing some research into the censorship debate surrounding these sites, and think a key way to get the public properly engaged is to facilitate our own form of online debate. Two members of our group could write an opinion piece on either proposition, and then allow user's to contribute their own arguments. The Economist Debates are a really good model, maximising the medium through ongoing polls, user comments and links to 'background reading.' We would probably steer away from the formality of the 'Oxford Style' debate as our target audience is broader than The Economist. However the overall format and levels of interaction looks like great model to go off if we want  to generate similar levels of user participation.