Locale Settings on the Computer (Score 1)

I've noticed that changing the locale settings of the PC can affect what ads are displayed. I'm in the US but I run my Mac in Japanese mode and I regularly see adds for things in Japan. (At least, Adult Friend Finder thinks I'm in Japan... I didn't know there were so many hot foreign women living there!) I haven't tested on Windows, but I think running a different language browser (for example, Japanese Firefox on an English Windows) will also cause this problem. I'm guessing some sites look at the user agent of the browser for language settings.