I get what you mean - people post irrelevent, flippant comments when you'd rather see relevent, serious comments. I've not seen them much myself because I usually just download the videos and watch them offline. But when I have seen the comments, they're not usually very interesting. I uploaded and published a rare live recording of a band to Podomatic.com once, and asked if anybody knew the date and place of the performance, because I wanted to know, and the only comment I got was by somebody who said how sexy he thought the lead singer was. 