A security researcher has released a tracking cookie that he claims is nearly impossible to remove. Dubbed evercookie, it is designed to raise awareness about the ease with which Web site operators can evade privacy tools designed to eliminate shield visitors privacy. The cookie is capable of storing data in several types of storage containers on a system where it is installed, then regenerating itself in the event that a user clears out his or her browser cookies after a Web session. It also leverages a number of HTML extensions introduced with HTML5, the newest specification for the Web.
Source: https://threatpost.com/researcher-claims-evercookie-cant-be-removed-092210/74502/