You’ve probably never even thought that “browsing the web privately” was something that you needed to take extra steps to do. Most people think all web surfing is relatively private and nobody is really paying any attention. Unfortunately, there are many people, particularly in the form of marketers and advertisers, who watch almost every website you visit and record almost every click.
http://robertsiciliano.com/blog/2013/04/19/5-ways-to-browse-the-web-privately/