Comments are a function that is used on YouTube. This function is used to put a comment in the bottom of a video.
Comments where surprisnigly not used on the beggining of YouTube. Thats because on the beggining of YouTube it was a dating site, on mid 2005, when YouTube's premise changed the comment section was created. A lot of people though that the first comment ever posted was from the user COBALTGRUV, wich was posted on July 12, 2005, on Jawed's video, Me At The Zoo. But the actual first comment ever posted on YouTube was posted by a guy called Marco Cassé, wich was succesfully posted on June 14, 2005, the comment said "LOL!!!!!!" It is rumored that this comment was removed.