I thought somebody at sitepoint would have noticed this by now - there has been text instead of an ad in the footer and the ads have been misaligned for nearly 24hrs. I use IE but I doubt that is the problem; probably something to do with the ad server?
I never watch the ads 
But I just checked and all seems normal (FF).
That’s strange as I have had the problem on two computers; anyway a screen shot:
The same issue was reported in this post:
I’m not seeing it, but I’ll pass it on for investigation. Thanks.
I think it can be zoom related (in the visitor’s browser settings). I’m seeing it only on my desktop/laptop, if I zoom a page > ca. 125%; with a text-only zoom (for browsers which can do that) nothing happens. So if a visitor has set his/her browser on > 125%, they are dropping. Maybe that’s the reason.
A strange thing is that in Rubble’s screenshot not the third image is dropping (as in my browsers), but the drop is coming right after the first one. 
Anyway, it are all nested iframes (iframes in iframes), with plenty javascripts in it…