I think the www.designsponge.com ad is performing well. The first two full days have generated just over 300 clicks. While this may not sound like a lot, keep in mind, this is from a demographic that is a very good fit for DPW and these folks may return day after day!
Further, after much tweaking of the search interface, including adding the Quick Search sidebar, I am seeing a significant uptick (10 fold) in the number of visitors that are searching vs. simply viewing the default pages. In fact there are more searches, now, than simple default views.