I was going to throw up the old addage, where google knocked "Text Link Ads" from the rankings, but still had links to it in the sponsor ads (and were aware of it: Matt Cutts did refer to the company a few times, and was challenged about it in a conference a while back), but it appears those links have gone, so I can't comment on it.
Personally speaking. I hate linking for pagerank as it skews the rankings. Good content should be the one brining good revenue, not necessarily good marketers
