Would you mind elaborating a little on where you draw the line? In my mind "SEO" means adding the correct meta tags to the html, but I suspect that's because I have approximately zero wisdom on the subject.
SEO and SEM (Search Engine Marketing) get mixed up a lot. SEO vs SEM is like aesthetics (color theory, composition, etc) vs a billboard ad. The latter cares about the former, but the former is innocent.