You're totally right about that symbiotic relationship. We were aware of that risk in the early days when AdSense launched, we saw some very innovative and gross exploitation and created some policies to rein it in. But ultimately if Google makes a buck coming and going, they will do that.

Wasn't there a big story last year in the wake of the DOJ antitrust investigation about Google manipulating search quality to boost ad revenue? I can't put my hands on a reference now, in part because Google is so bad at search these days I can't find anything more than a few months old.