> isn't really a great way for websites to track users. You are quite right, this is true, however it's not really about that. Firstly this is one technique t

> isn't really a great way for websites to track users. You are quite right, this is true, however it's not really about that. Firstly this is one technique that when combined with other information becomes more valuable. Secondly it's not for websites to track users, it's for tracking companies to track browsers across multiple websites. For example: A credit scoring / user tracking company that your bank uses. You log into the bank system. You visit other websites which have a tracking system. The bank gets a profile of the types of websites you visit, to better profile the types of customers it has. The tracking service has a profile of the types of users that it sees, to better place advertisements for their other customers. Thirdly, a fingerprint of this kind is more of a multi-dimensional nature, than just a hash of the results. It allows for some variation, it will also update itself based on other information. For example "oh it looks like they have added a new font, but the other information is the same, and their behaviour across all the sites we track them is the same"...