[tkb]

I too had a small web site with M4 around 1999/2000. Why M4? Because I'd learned enough of it to be useful/dangerous when wrestling with Sendmail, and it seemed to do the trick (at least when the trick was simply "be easier than manually editing lots of HTML files every time there's a site-wide change").

I suspect I was never doing anything complicated enough to encounter the gotchas mentioned by other commenters...