To combat the cookie’s flaws, advertisers and publishers are increasingly turning to something called fingerprinting. This technique allows a web site to look at the characteristics of a computer such as what plugins and software you have installed, the size of the screen, the time zone, fonts and other features of any particular machine. These form a unique signature just like random skin patterns on a finger. The Electronic Frontier Foundation has found that 94% of browsers that use Flash or Java – which enable key features in Internet browsing – had unique identities.

AdStack a San Francisco start-up comapany have developed a technology that allows firms to send an email but deliver the content only when a user opens it, giving the sender a chance to change the message in a few milliseconds. The email is sort of like a picture frame, with the content delivered interactively much as a webpage. They aim to deliver a personalized message at the right time.

Fingerprinting allows marketing companies to identify 98% of Internet users and use it to personalize the advertising.