a) The best people of your side, may not be the best people to talk to the other side. Think rhetorics and clarity, vs depth, knowledge and insight. b) It can be gamed, especially online, by people being moles. c) There is usually a lot of context, "axioms" that make something "obvious" to you, but are too many to easily say to the other side.

http://www.opposingviews.com/ does a good job here. It lets you see the best arguments from either side at least.

Edit: I dunno what came over me. I had the address transposed in my head. I meant to post a link to debate.org.

Where? I just paged through and saw a bunch of mildly controversial news headlines (which did seen an intriguing collection of conversation starters, like hard income limits for Medicare), and then a pile of ad spam for "hot celebrity pics" and testosterone for sale.

Corrected, with apologies.

Thanks! Debate.org looks good. It even has three sections for highbrow, middlebrow, and lowbrow; labelled dabatew, views, and polls respectively.