I'm active on several English language boards. All of them have a majority of American posters, with a bunch of Brits and Canadians, plus a few Aussies and Kiwi's. Anybody else is a random friend who happens to understand English well enough to participate. I expect there are bunchs of Spanish language boards, or Japanese boards or whatever, where an American shows up once in a while to practice their language skills.
Basic good manners: don't barge into some stranger's house and start griping about the type of company he keeps.