In both cases (on separate accounts, same computer), it said "Thank you, xx xxxx! Let's see the magic..." (I used the same user name and IP address from both).

In both cases (on separate accounts, same computer), it said "Thank you, xx xxxx! Let's see the magic..." (I used the same user name and IP address from both). Restarting (exactly the same version) of Firefox a second time and revisiting the site gave: "Are you anonymous? Do you think that switching to your browser's private browsing mode or incognito mode will make you anonymous? Sorry to disappoint you, but you are wrong!. Everyone can track you. You can check it out for yourself. Just type your name below." Which seems to suggest that whatever the site does failed in my (admittedly unusual but still simple) case. However, I have little doubt that my (rather atypical) setup could be fingerprinted accurately - assuming, of course, I was part of a big enough minority to be worth advertising to. N.B. other local factors could affect the results here; the more obvious ones are local DNS and a firewall between the ADSL router and the LAN.