https://www.pcgamer.com/overwatch-endorsements-and-looking-for-group-features-are-already-working/

It's only been a few weeks since the "looking for group" feature and endorsements were rolled out to Overwatch, but they're already having a positive effect. Game director Jeff Kaplan shared some early stats in a brief forum post indicating that abusive behavior has gone down dramatically in the Americas and Korea since the features went live. 

Competitive matches containing abusive chat were down 26.4 percent in the Americas and 16.4 percent in Korea, Kaplan said, while the percent of daily players being abusive has shrunk by 28.8 percent in the Americas and 21.6 percent in Korea. Other stats aren't available yet, as Kaplan said he's "just sharing what progress we had" so far.