The problem is this:
<div id="content-ad">
The body content is wrapped in a div with "-ad" in its name, which most ad blockers will trigger as an ad. If you're using Firefox and AdBlock Plus, you can look at the list of blockable items (ctrl+shift+v) and you'll see that there's a rule "###content-ad" coming from "Fanboy's List (English)". From there you can edit or disable the filter, but if you do so you'll probably start seeing legitimate ads elsewhere.
This is not unprecedented. Ars Technica did something similar a year or so ago (they called it an "experiment" and ran it for 12 hours, and then belittled all of the adblock users in the comments -- I haven't bothered going back to Ars since).
You might able to get around this by writing a custom user script that changes the class id, but depending on when that user script runs vs. when abp runs it may still block the content.
IMHO, sites that block content from adblock users are not worth my time, so I'm not going to put much effort into bypassing it right now.