possibility of html output filtering

[Tyblitz]

Yes, all plugins have this at their disposition. Have a look at http://get-simple.info/wiki/plugins:hooks_filters.
Basically in your plugin file you just do:

PHP Code:

<?php
function myFilter($content) {
  $regex = '~<!--.*-->|<span class="testonly">.*</span>~'
  return preg_replace($regex, '', $content);
}
add_filter('content', 'myFilter'); ?>