What gets me is the title of this thread.
"American's use of 'then' instead of 'than'"
Unless you're speaking of one American in particular, shouldn't it be "American
s'"?
its/it's, your/you're, lose/loose, et al. really get to me. I'm also appalled by the increasing number of proofreading mistakes in books, periodicals, and "official" websites. *sigh*