This has long been a security issue and I had many conversations with Mirimir over the years. The specific issue is how they capture the hardware details of the computer where the browsing is happening. Its the reason we decided to use Virtual Machines for things since our hardware is virutal and in my case changes Mac's, virtual board components, etc.... every single day. In this fashion when I log back in the hardware is not at all the same as it was last time, if that makes sense. TRUST ME you can use VPN's and other countermeasures but if the physical machine details, which can be captured, remain the same you will fall to fingerprinting. Paste from inside linked article: "Fingerprinting involves building a user profile using information about a device's software and hardware, rather than the use of something like cookies, "
