some good posts on here so far... thanks for the insight.
again, it's funny that an american accent conjures images of a tourist so consistently. i would venture to say that there probably isn't a single accent that we Americans equate with tourism or tourists. i think the loudness while traveling is partially part of our culture (i know it grates on me sometimes) and also because of unfamiliarity with our surroundings. being more used to talking to strangers at home, it's only natural that we be more extroverted in public than the locals are used to. i'll admit, we in the U.S. are insulated a bit... we have a large country and we do happen to export a lot more ideas/media/ass kicking than we take in.
i don't mind saying some of us are much more ignorant of international norms... but few of us are outright rude. if you see an American making a fool of him or herself overseas... try to assume the best of them and do what you can to clue them in. we're used to strangers talking to us and would almost always appreciate a bit of insight from a local.