[aaronsw]

They have a nofollow meta in the head of the page, which according to http://www.seobook.com/robots-txt-vs-rel-nofollow-vs-meta-ro... is as good as rel="nofollow" when it comes to PageRank.

[Natsu]

If the paid links don't pass PageRank, I don't think Google has a problem with them. I've seen Matt Cutts say that quite a bit lately, because Forbes was caught doing this (again).