Anyone know if research has been done to see whether the background color of a website effects click thru rates on ads?
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The best results are achieved, if the ad blends in to the rest of the site and it's not necessarily apparent that this is an affiliate or Adsense /Yahoo link. If you place the link you want people to click above the fold (in the initially visible part of your webpage on the screen), and either let it blend into the navigation of make it stand out by letting a lot of free space around it, you'll see click throuhg rates increase too.
This is design (and probably niche) dependent. In some designs blending is good, in others sticking out like a sore thumb works wonders. There are no set rules and anybody promising there ARE such set rules are just setting you up. Since blending often works, an easy way is to just blend and hope it's the best way. For higher traffic sites it becomes logical to test different color-combinations (usually derived from the design) to see whether the CTR can be brought up.
It depends if you are targetting contextually or with banners. as to what the answer is. Sometimes it is to blend sometimes it is to make it stand out and be noticed.