If you were to log in, you'd be able to get more information on your fellow community member.
Don't Assume that Everyone is an American
This is important if you're selling something.
- Not every country uses the same number of digits in their phone numbers.
- Not all zip codes (called postal code in some countries) have the American format.
- Not every country is divided into states(!).
Don't Use Long Option Menus
Some sites let you select the country you live in from an option menu with several hundred entries. This requires lots of manual dexterity, and on most Unixes (I don't remember how it is under Windows and Mac) the cascaded menus will appear on top of each other when reaching the right border of the screen.
Why is that a problem? Because the "more" item at the bottom usually will appear at the same place as the "more" item in the next cascade, thus popping up all the cascades which exists!
Instead you could use a list box, where one can scroll down to the appropriate section. Or let people write in...