[kuschku]

In the beginning, Google’s founders said

> The goals of the advertising business model do not always correspond to providing quality search to users

> For this type of reason and historical experience with other media [Bagdikian 83], we expect that advertising funded search engines will be inherently biased towards the advertisers and away from the needs of the consumers.

> Furthermore, advertising income often provides an incentive to provide poor quality search results.

And most importantly

> But we believe the issue of advertising causes enough mixed incentives that it is crucial to have a competitive search engine that is transparent and in the academic realm.

I think especially the last statement shows very well that they were ideologically opposed to advertisement-funded search engines.

Source: The Anatomy of a Large-Scale Hypertextual Web Search Engine, Sergey Brin and Lawrence Page. http://infolab.stanford.edu/~backrub/google.html

[arbitrage]

In no way. The last statement very clearly is ambiguous, and does not preclude the creation of ad-driven revenue. They are in fact saying, "These are the problems with current ad-driven search services" and very heavily implying "we're going to do it differently."