Whitey - 10:04 am on Mar 2, 2010 (gmt 0)
It's a few years ago , but I've seen sites purchase paid links in a large scale network and both seller and buyer were penalised on the specific sites . With the links removed by both buyer and seller the sites came back. It was a a warning shot , so I'm not sure what would happen if the incident stayed around for a bit longer.
Maybe a more severe penalty - i don't know.