I've played in this space! A few years ago, I half-assed the world's worst startup for asynchronous political debating that focused more on identifying and understanding opinions as opposed to expression and dialog, because dialog necessarily breaks down to dichotomies and outgroup homogeneity which are exactly the problem. I never really figured out how to elevator-pitch the damn thing, but here are some blog posts I wrote back in the day: http://blog.agreethepeople.com/
If you do follow that link, start at the bottom and work your way up. And let me know what you think!