It's pretty much universal with AdSense. If you know anyone who makes a significant amount of money, ask them about it. Or just browse the AdSense board on WebmasterWorld.
I have personally increased revenue by over 100% by making small color and positioning changes, and this is also fairly common (I cited 20-30% because I wanted to be super-conservative in my claim).
But here are some examples:
From Google's official blog: Removing a border from an ad doubled revenue to $650/day:
I have personally increased revenue by over 100% by making small color and positioning changes, and this is also fairly common (I cited 20-30% because I wanted to be super-conservative in my claim).
But here are some examples:
From Google's official blog: Removing a border from an ad doubled revenue to $650/day:
http://adsense.blogspot.com/2006/05/unobtrusive-ads-can-boos...
Palette swap doubled clickthrough: http://www.cyberindian.com/web-marketing/article.php?article...
Webmasterworld thread: Most people did not disclose percentage, but some did (85% increase, 100% increase, etc)..
http://www.webmasterworld.com/forum89/14556.htm
There are endless examples.. just Google it.