internetheaven - 9:44 pm on Feb 23, 2013 (gmt 0)
The reason? Because I had not configured a color for visited links in some of my ads.
Ummm ... what? Seriously?
I changed the site to the new 300x250 ads around the start of January. Surely they're not going to stop tracking clicks after the 12th of Feb because I haven't gone in and tinkered with the colours in the past 6 weeks?