I don't think they have to 'like it' so much as agree that it's a valid review of their stuff. I posted plenty of negative reviews when I was working there but I still got my money, because everything was targeted to the song.I heard from this website a few days ago, some people were saying they pay you around 5 cents of dollar per comment, but the owner of the song that you comment about have to like it. They have a rating system so you have to do a good job. Once they used to pay 0.15 dollars per comment, which is a nice price, but since now they reduce it, I'm not sure it's still worth it.
I think you can still theoretically make that much per review, but after 150 reviews I was still pretty stubbornly stuck at three stars out of five. I'm betting they don't move people up the ranks very often to keep their costs low. Tisk.