by @cgutteridge
This page is hosted on

The content in the red boxes is hosted on different sites. Such sites can see what page you were viewing and what your IP address is, or even use cookies to track exactly who you are. This is fine unless you wanted privacy in your life. You don't need to click the 'like' button for Facebook to know that you were on this page, just viewing this page with a 'like button' iframe is enough. Facebook knows you were here!

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