Consumers are attracted by high-quality search results. Search engines, though, essentially compete against themselves because consumers are induced to substitute away from advertisement links when their organic counterparts are of high quality. I characterize the effect of such revenue cannibalization upon equilibrium quality when search engines compete for clicks. Cannibalization provides an incentive for quality degradation, engendering low-quality equilibria—even when provision is costless. When consumers exhibit loyalty there is a ceiling above which result quality cannot rise, regardless of what the maximum feasible quality happens to be. Seemingly procompetitive developments may exert downward pressure on equilibrium quality.