It looks like the BlogSnob SimpleAds Exchange script is changed by Pheedo. The code is now generating two ads, vertically places. This is messing up the right hand column. I have to check with them and see how I can customize the ad.
I have changed the referrer script from True Fresco to Blogtricks. I will probably put a maximum on the characters allowed in the referrer string, in order to prevent the column layout to look strange. I am planning to add some new scripts in the near future.
[Editor's note to Adam Kalsey at Pheedo: Thanks for your comment and help with ad.]