I don't think it really has. I'm blessed to have plenty of fascinating discussion in my life in general, so the little bit I've tried to have on Reddit hasn't really affected my general ability to talk about things. What I think Reddit has done, is made me wary of attempting that sort of discussion online. Why bother attempting to have a reasoned, well thought-out argument, when you're just going to get flamed into oblivion if you happen to disagree with the "hivemind". That said, there are places on Reddit that had, and still have, very good discussion. The smaller, fringe boards have always been fantastic for me. The ones that were tightly focused on one hobby or issue and didn't have more than a few thousand subscribers. I think the problem Reddit has, is that for the larger site, it has lost any sense of community.