Potential revenue stream
John Battelle has some thoughts on a potential revenue stream for Google that would probably violate their "Do no evil" policy. It involves doling out top search results on structured searches (finance, for example) for some sort of business arrangement (cash). This would also violate their long-standing policy of not tainting their search results with advertiser revenue. However, they may be tempted to do so for a few "special" searches.
As long as people trust Google, the business model can survive. However, once the moral authority of providing unbiased search results dissipates, the jig is up. And therein lies the problem. Google will constantly be torn between two forces: 1. the desire for short-term profits in the form of specific, measurable revenue streams and 2. the necessity to maintain the aura of objectivity which underlies the long-term viability of their business. I will let the reader decide which of these forces has historically prevailed.