europeforvisitors - 4:12 pm on Jan 7, 2008 (gmt 0)

As you pointed out, some icons--such as printer, e-mail, and shopping-cart icons--are already de facto standards that most users recognize. Beyond those half-dozen or so icons, things get tricky, because sites are organized in so many different ways and and the meaning of an unfamiliar icon is in the eye of the beholder. (Just the other day, I was reading an airport terminal map, and I never did figure out what image the ATM icon was supposed to represent.)