I generally try to utilize address "tags" for this sort of tracking, for example username+tag@example.com (http://en.wikipedia.org/wiki/Email_address#Address_ta

I generally try to utilize address "tags" for this sort of tracking, for example username+tag@example.com (http://en.wikipedia.org/wiki/Email_address#Address_tags http://en.wikipedia.org/wiki/Email_address#Address_tags). Unfortunately many websites seem to think that '+' is not a valid character in an email address. Very annoying.