I just did a Google search for “Project Gutenberg.” Rather than finding the Project Gutenberg website, Google filled the results with entries from its own e-book catalog. A Bing search took me right to Project Gutenberg.

I filled out a complaint form (Google has a link at the bottom of the page.) A few minutes later, it was giving correct results. Questions: was this a broken server, or a normal result? Was my later search influenced by my complaint? If so, did it only affect my search results? No matter how well-intentioned the folks at Google are, there is too much incentive for bias, and it is too hard to detect* for bias not to creep in over time.

*See Appendix A of this academic paper for a discussion of the dangers of search engine bias.