I try to click all four of them everyday, and I will put the rainforest (and maybe the others) one of my website when I get around to it.

However, I don't think it's the fact that not enough people click the button that it's risking to go down, but the fact that not enough people buy items from their sponsor's stores. I mean, if I was one of those big stores I wouldn't be sponsoring a site and paying for free stuff unless I got something in return (I'm thinking for a big company's standpoint here, not my own I like to help out even if I don't get anything in return).