A large percentage of websites have social network buttons and you probably used them. Every time you visit a website that has “Like”, “Follow” or “+1” buttons, even if you don’t use them, the social networks sites can track you. Facebook is (or was?) tracking you even after you log out. What this means? It means that social networks sites know what sites you are visiting and “learn” your interests. I don’t know about you but I don’t like that and I like my privacy. If you think that this is not a big deal then you are wrong. They track you on every website you visit that has the social network buttons, even if that website is illegal. Even if you don’t want to visit an illegal website you may do it, another website can create a pop-up with illegal content or redirect you to an illegal website. Social networks may not have the obligation to report you if you have visited websites with illegal content but if police asks for your records they should give them. Do you worry about your privacy now?
There is a solution to that and you can protect your privacy by using a FireFox extension (add-on) called “Priv3”. It is free and it allows you to surf the web without the social networks tracking you, even if you are logged in. Those third party sites will learn which websites you have visited only if you want them to, that means if you use the buttons. Priv3 currently protect your privacy from Facebook, Twitter, Google+ and LinkedIn.
Source: [Priv3]