There's really a lot more you can look at here. Lot's a prior art on super-cookies and fingerprinting:
Both linked in the Sources & Confessions modal at the bottom. Cover Your Tracks is the spiritual ancestor of this whole piece. amiunique is more rigorous; this is the editorial cousin.
Another info leakage feedback tool:
Hmm interesting. I tried the EFF site and among other things it told me I'm on "MacIntel".
Gave me a scare, thought I'm still somehow running an x86 build of Firefox.