Debatewise.org is a site I think about every time I see an argument on Twitter or in a comment thread on some blog or other. The reality of the site falls very far short of the promise on offer:
[…] a place where the best possible arguments for one side are listed next to the best possible arguments against. These arguments aren’t created by one person, but by like-minded individuals collaborating to form the strongest case. This allows people both to easily compare the pros and cons and also to come to a decision safe in the knowledge they have the best information to hand.
In essence, the site breaks every question down into component issues. Then the pros and cons of each sub-point is strengthened and revised (wiki style) as users vote on how much they agree with one perspective or the other.
A quick browse of the site reveals that it is barely a notch above Yahoo! Answers on the scale of intelligent debate, but I still think there is potential in the format. I can see discussion sites like Have Your Say or Comment Is Free making great use of a commenting system modelled after this. A WordPress comment plugin offering similar functionality would be interesting too.