Just like AOL way back in 2006
Remember the flap over 650,000 user's search history being released for "research" purposes?
If not, go to https://en.wikipedia.org/wiki/AOL_search_data_leak and read about it.
Then stroll over to http://search-id.com/ and play around.
I have used it as an example for years when I teach security to users at NGOs, and is why I use https://ixquick.com, https://startpage.com and https://duckduckgo.com for my searches. Ixquick has the only EU privacy seal. Startpage is a privacy protecting proxy for Google by the Ixquick people. Plus I get better results that I could get from Google direct. See http://dontbubble.us/ for one of the reasons and take a peak at http://donttrack.us/ for what they do with your search queries.
On another note, the Ixquick/Startpage people have a privacy protected e-mail system that is PGP encrypted called Startmail. End to end encryption and auto expire.
This e-mail may, and probably does, contain factual errors as well as errors of logic, organization, grammar, and spelling. They are included at no charge, unless, of course, you'd care to make a donation.