White space doesn’t affect semantics outside tags. Inside tags it usually only accepts two spaces and anything more than that still only accounts for two, unless you add ’s or something of that nature. The white space could affect file size though. And also if you are importing .txt files into Flash and other odd cases white space will affect the outcome.
@cnwtx Semantics matter for those that may not be as fortunate as us. Accessibility is always something that should be on your mind and a sound semantic structure helps screen readers and therefore those that use screen readers.