[kh99]

Well, there is also a parentlist, so I think what you'd want to do is check the parentlist for forumid 1 (if 1 is the actual parent forum id). But the problem is that parentlist is a comma separated list, so in_array() won't work. You could call explode() to make an array, but you can't use explode() in a template condition. So I can't think of any way except to have a plugin to help out. For example, you might make a plugin like this:

$show['forum_google_ads'] = in_array(1, explode(',', $foruminfo['parentlist']));

then in the ad manager use

<vb:if condition="$show[forum_google_ads]">
...
</vb:if>