When Cheerful Ghost launched I checked out the League of Legends community and it was a cesspool of horrible. Using both positive and negative reinforcements RIOT is doing something that seems to have worked.
As always, another rad episode of Game/Show.

I like the explanation for why RIOT's system appears to be working. Using a combined punishment/reward system, with its roots in the community, they're able to publicly shame those responsible for bad (or unwanted behaviour) and publicly praise those who create a more harmonious gamespace. Contrasted with the typical approach of primarily negative disciplinary action against players, RIOT's approach appears to be working.