In an effort to optimize the effectiveness of the VeriSign.com homepage banner, we recently did some testing to maximize response rates. The homepage banner is a multi-message banner with four 'buttons' each representing four individual messages.
The goal was to test which sequence of buttons was the most compelling and therefore, garnered the most clicks. We were not testing the copy, layout, imagery, or color palette as part of this test; this was previously done in usability testing.
Along with the control, we deployed different versions of the banner with the order of the first button being displayed varying. What we found was that the button positioned first (from left to right) always got the most number of clicks - likely by virtue of being the first and easiest and quickest to access, and the other three buttons got varying numbers of clicks.