How did YouTube culture come to be?

There seems to be a standard on YouTube. When performing some artist look into the camera, some stray away from it the whole time and are just into facial expressions. (I love the latter). There also seems to be a commercial approach as if there is an acknowledgement that “this will be watched by YouTubers.” I grew up right in the beginning of all this, I always thought it to be silly (I don’t hate it at all) that the audience was “YouTubers”. Recently it looks to have become a forum for hardcore bashing or extreme praise, put simply I feel like it serves as a forum for the social mob.

What are your thoughts on the overall YouTube culture?
Pros, cons?