Well...
* What language settings does your computer use? en-AU? en-GB? en?
* What are your date format preferences? mm/dd/yyyy? yyyy-mm-dd? dd/mm/yyyy?
* What time of day/timezone is your computer set to?
* Have you ever visited their site without going through a proxy from a different geolocated IP?
* What's the turnover of accounts on a given IP?
* What was the nationality of the payment source? BIN/IIN?
Biting the hand that feeds IT
