I don't know, I have ad blocking turned on, plus dozens of blocking rules added by me and your link (
http://c.moreover.com/click/here.pl?r576416533) works fine and view source is normal.
If you view page info, there's an entry for "other" called showads.js. It's listed as being "text/html". If you look closer (by dragging this to the desktop) you'll see its URL is
pagead2.googlesyndication.com/pagead/show_ads.js
I have this url blocked with a rule
.*googlesyndication\.com/.*
So, possibly, blocked scripts (or pages designed to be loaded/written with a blocked script) will yield only an empty body tag in view source.
This seems fine to me -- after all, I'm the one who blocked it -- but perhaps there cold be a better indication that this is what's going on, so the user doesn't think there's an error.
Maybe the page info list could display ad-blocked items in italic, or another color, similar to how AdBlockPlus for FF does. When you view the list of "blockable items" with AdBlockPlus, blocked items on the page are flagged as such. Even nicer, clicking on the blocked item shows the rule that blocked it. This is helpful to edit overzealous rules.