It's a pretty accepted fact that a lot of MOBA players are jerks. Swearing and passing blame are common amongst losing and even winning teams when playing with the public-at-large. It's the reason why I've never solo-queued and always go in with at least one friend by my side. It's also the reason that Valve implemented a new reporting system last month. Valve is now sharing some of the information gathered from this system in a detailed blog post.
Perhaps most interesting is that since the new system, they have seen a "35% drop in negative communication interactions" and "60% of players who receive bans go on to modify their behavior and don’t receive further bans." Those are some seriously impressive numbers, and really make it seem like the new system is working, at least for now.
Really, I just hope that Valve makes more blog posts like this one, sharing some great information with the community about not only results, but the thought process that got them there.