I just added an Adsense ad code to a new blog I’d created. So far so good, the ads display as expected.
Except: upon loading each page, there is a momentary flash of pale yellow where the banner will shortly appear. This is undesirable behavior, not only because it is a visual distraction, but because it calls out my advertising banner as a distinct block separate from the rest of the page, perhaps contributing to banner blindness.
After a bit of poking around, I solved this problem and eliminated the yellow flash. It turns out that this was happening because I was using the Twenty Eleven theme for WordPress. I think this problem might also afflict the Twenty Ten theme and others, and probably a colored flash will show up for those using certain themes for other CMSes like Drupal or Joomla. Update: The yellow flash also afflicts the new Twenty Twelve theme, which can be corrected the same way.
That’s all! This is certainly a somewhat obscure problem, but I thought it was worth writing up if it helps a couple people get on the road to blog success a little faster.