The medium and large rectangle square off

When talking about optimization here on Inside AdSense, we frequently encourage readers to use the 300x250 medium rectangle. But we've also talked about how bigger ad units tend to perform well, so a few publishers have asked us, "Should we be using the 300x250 medium rectangle or the bigger 336x280 large rectangle?"

We took this question to our Optimization Team, who gave us insight into the strengths of each ad format:

• The 300x250 medium rectangle is a widely supported format that advertisers often use when designing their branding and rich media campaigns. Using this ad format and opting in to both text and image ads may generate more placement targeting opportunities, which will help drive up competition for your ad space and should lead to higher earnings over time.
  
  
• The 336x280 large rectangle tends to have a higher clickthrough rate due to its larger size. It often performs well on text-heavy pages where it's integrated into the content.
  

Our optimization specialists noted that performance of these two ad formats can vary from site to site, so they can't definitively say that all publishers should always use one format over the other. Just like with all other customization options, they recommend experimenting with each ad format for 3-4 weeks and measuring performance using custom channels.

What's your opinion? Feel free to leave us a comment and let us know how the medium and large rectangles have performed for you.

Posted by Arlene Lee - Inside AdSense Team