Blizzard introduced an "endorsements" feature to Overwatch last summer that enables players to rate others who are good teammates. The idea is to discourage toxicity by rewarding good behavior, rather than just punishing bad, and it worked: Just a few weeks after the system went live, game director Jeff Kaplan said that abusive chat in competitive matches had dropped by more than 26 percent in the Americas and 16 percent in Korea. The percentage of "daily players being abusive" was down even more dramatically.
Things have continued to improve since then, according to research scientist Natasha Miller, who said during a GDC talk (via PC Games Insider) that the system, which includes endorsement "levels" and randomized loot drops, has resulted in a 40 reduction in matches with disruptive behavior, with between 50 and 70 percent of players handing out endorsements.
The positive reinforcement offered by endorsements is apparently a powerful selling point. "If you’re not consistently getting endorsements, if you slip up, you’re not going to get endorsements and your level is going to slip," Miller said. "This often causes players to want to get that level back and keep going, which offers a path to redemption."
To help ensure that it was on the right track, Blizzard also "put out a server to see if players perceived the endorsement system to be the reason for the decrease in negative behavior," she said (via Variety). "Perception can be different than reality, it was close in this case. Players agreed the system was working the way we intended it to."
Miller said that Blizzard will continue to refine the endorsement system in the future.