Nearly all companies with a big Web presence, and search engines in particular, are known for gathering the user’s browsing history and other personal information to improve on the services they offer, such as by offering better targeted advertisements.
A preliminary report compiled by the Federal Trade Commission (FTC) addressing the lack of transparency and user control over how companies gather Internet browsing data from their users, proposes a “Do Not Track” feature for Internet browsers that would allow users to opt out completely and protect their privacy.
Because end-users don’t always have control over the amount or even type of data that is stored by companies, there’s a chance that sensitive data could be inadvertently sent to third parties or used by the company against the user’s wishes. Google allows users to keep this data in check for those who own a Google account, but this is not the case for all search engines. Unless explicitly blocked, all the major search engines gather history (including searches, visited pages, etc.) for a period of time that usually ranges between three and 18 months.
While this kind of information gathering can be beneficial to improve the user experience, it has caused problems in the past. Yahoo, for instance, has been criticized for providing Chinese authorities with sensitive information that has helped convict local journalists and political activists on several occasions.