McMohan - 10:33 am on Jul 2, 2012 (gmt 0)
I personally would only spend money trying to appear in ads that were relevant to my business
That's a great argument to put forward claaarky. I once advocated legalizing paid links. Why would anyone pay so much money buying links if the site were not relevant for what s/he is trying to rank for? Stronger the signal sent by paid links, stronger is the intent to rank for and possibility of relevancy. If the user metrics is positive, so much the better, that business will sustain. If it isn't, the site will no more invest on paid links. It could be self-sustaining.
The downside is, per Google, you are still manipulating its algorithm (which is suppose to be shielded from the PPC side) by spending on PPC. The issue has only shifted from links to ads.