John Coggeshall runs all his pages through his Smarty Tidy Output Filter [1]. Since Smarty does some caching this should not be a speed drawback. I just wonder if it does not break minutiously designed sites using CSS e.g. for positioning instead of images like with spacer.gif. But this is eventually no problem if tidy i only applied on the (inner) site content rather than on the site\’s main design.
[1] http://coggeshall.org/show_source.php?filename=outputfilter.tidyrepairhtml.php
