In February 1998, a small Pasadena company named GoTo started auctioning placement in search results they bought from other providers. Six months later, they claimed to have more than a thousand paying customers. According to GoTo, you didn't need fancy algorithms to determine relevance, just the invisible hand of the free market. Any company bidding for placement at the top of the results must be a good match for the term being searched. At Google, we found that concept ridiculous. Bidding-based ranking was clearly inferior to results based on an algorithm. Bidding was driven by imprecise humans. Humans bad. Math good. We knew about GoTo, but we discounted their "non-technological" approach. That proved to be unwise. We gave them a head start, and for the next four years we would fight them for supremacy in the online advertising market.