From a SEO point of view maybe i don't want to have the real last modified presented there

Another question is what happenes whith pages that automatically generates content? Do they ever get updated ?
For example a Startpage that has a news(topics)block presenting the last 5 post right below the normal content. So you have a WYSIWYG block whith an anytopics droplet adding a news section at the end. Anytopics changes the page content every time you post some additional news on you news/topics page but last modified isn't changed at all.
This Droplet is a really nice idea, but far from being something that is feature complete.
Its a special solution for a certain problem and thats what droplets are for.
Good work!
Personaly i would prefer not having an incomplete metatag presented on PageId 0.
global $database, $wb;
if (PAGE_ID>0) {
$query=$database->query("SELECT max(modified_when) FROM ".TABLE_PREFIX."pages");
$mod_details=$query->fetchRow();
return '<meta http-equiv="last-modified" content="'.date(DATE_RFC822, (int) $mod_details[0])." GMT". '" />';
}