One aspect of search engines that worry me is the privacy aspect. Search engines use this information for their behavioral targeting. Look at the grid on the cnet page.
http://news.cnet.com/2100-1029_3-6202068.html
So has this issue of privacy ever impacted you on which search engine you will use?
There are two considerations here for me.
First, if the data is being used to target advertising to me in search engines they are wasting their time as I ignore the advertising. If you are someone who pays attention to those ads perhaps it would be a good thing for you to get target ads in your search results. Also, unless your searches are of things that you would find embarrassing then is there really an issue.
Second, and potentially more disturbing, is that the current president has announced that he is going to appoint a Cybersecurity Czar with a broad mandate and broad powers to protect both government-run and private computer networks. This is a cabinet level position that is not voted on by the public or the congress. They are, in a sense, outside of the type of oversight that protects the constitutional rights of everyone.
The concern has to be, regardless of who is the president, that this position that reports directly to the president with no oversight and broad powers could easily be used to regulate and restrict what happens on the internet. If the Cybersecurity Czar deemed that the data the SE's gathered in terms of our various searches should be turned over to the government to protect these networks could they then use that data as a way of creating new laws and regulations to restrict and inhibit certain speech on the internet.
Let me be clear, I am not espousing any sort of conspiracy theory here nor do I think that there are black helicopters following me (the view from my office is beautiful and all I see are seagulls). I am simply stating a hypothesis based on the information that is out there.