To be quite honest, I don't have a clue. I asked about them once or twice before, and first heard that they weren't yet implemented, and then heard that they were but required something on the part of the editorial team (ie. they editorial staff need to make a "call for comments"). Is this true? I couldn't tell you. One thing is certain though - the staff don't even know what a "call for comments" is. I asked Marcus Yam about it and that was the first time he'd even heard of it. I've never seen anything in the CMS about it either.