A community that helps people stay up to date with things going on.
twitter. thats as deep as it goes. like how they try to get people to put hashtags in their titles despite no one using hashtags to find videos. corporations try not to turn everything into a homogeneous blob challenge: impossible.
it's funny because they tried to do this push a few years ago too where everyone new had an @ and they eventually dropped it because it was dumb. i guess whichever exec thought that was a good idea never actually left
YouTube comments were brought under Google+ shortly after that launched. After Google+ was cancelled, they may have adopted different appearances based on other websites' usage.
This change was added a number of years ago when youtube added (limited) hierarchical comment structures. When you reply to a comment, youtube automatically adds @USERNAME of the person you reply to. You can remove it, but it's relatively useful if there are multiple replies within a reply structure