Many people are asking: “how in the world they know that’s me returning to their website?” Well.. the most known reason is that the website stores a cookie on your local harddrive.
The most unknown reason is that they captured a fimgerprint by gathering information about your browser environment. A common way to achieve this is using java script. The website http://panopticlick.eff.org shows an online experiment how information of your browser can be used to create a unique fingerprint. Just try it out and stare at your screen. It’s amazing how few information is required to identify you using your browser’s interfaces. Additionally the tiping speed on your keyboard is also an information that can be gathered by a java script. Imagine how these methods can be used by companies and criminal organisations to personalize each www user.