C|Net discusses the privacy implications of search engines' policy to keep one's search history forever:
"It's only a matter of time before attorneys realize that a person's entire search history is available for the asking, and the subpoenas begin to fly. This could happen in civil lawsuits or criminal prosecutions."
Google is not alone, Yahoo and MSN also keep records of every query entered in the search box. The search phrases are matched to the IP addresses. "You are what you search for" could be a winning argument in court sooner than you think.
It comes as no surprise that services that try to make surfing anonymous are proliferating. There is even a Firerfox-based browser which promises to increase your level of web anonymity. Read more in Outsmarting the Online Privacy Snoops, Washington Post.
Alternatively, user testimonials offer a very positive view on Google. Dr. Karuturi writes more on how the most popular search engine has changed people lives. On a lighter note, Opera April Fool's page shows how search helps in difficult situations: What you need. When you need it.
FAQ: When Google is not your friend. February 3, 2006. CNET News.com