PANOPTICLICK

This piece of software tells you how unique your browser fingerprint is.
The less unique your browser's fingerprint is, the better as it means that it will be harder to track you around the web
No matter what blocking tools you have, some webpages will always be one step ahead, so you can never be too safe, my browser fingerprint was completely unique but I have managed to make it 'quite unique' meaning someone else has this same fingerprint!
It also provides some insight on other ways to solve fingerprinting and other tracking methods