To censor Internet forum comments by deleting them.
Usage is thought to be derived from Joseph Breen, who was head of censorship for the motion picture industry, and possibly a contemporary consumer industry editor with the same last name.
The moderator will breen my comment about government censorship.
The editor will be breening posts he doesn't like.
It's the combination of bro and queen, used for someone who you think is cool but don't exactly know the gender of. This term can be used for absolutely anyone.