Recent US government attempts to get informaiton from Google have made it clear that search engine users (not just Google users) no longer have any privacy, and as Declan McCullagh points out at CNet:
It's only a matter of time before other 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.
That type of fishing expedition is not legally permitted for Web mail providers. But because search engines are not fully shielded by the 1986 Electronic Communications Privacy Act--concocted back in the era of CompuServe and bulletin board systems -- their users don't enjoy the same level of privacy.
Danny Sullivan has an excellent post the case and the issues at Search Engine Watch.
