Dive Summary:

• Microsoft adCenter's new version 8 offers the option of rotation on pay-per-click ads, rather than defaulting to displaying the ad with the highest click through rate (CTR) most often.
• The long-awaited feature allows marketers to conduct more exact A/B tests and performance measurements outside of CTR.
• Users need to make the changes to one ad group at a time and there is no support for this new feature in Microsoft adCenter Desktop or bulk spreadsheets.

From the article:

Microsoft adCenter came to being in the summer of 2006. Generally speaking the advertising platform was greeted with open arms, but there were a few areas that were lacking.

One specific area of concern was how adCenter handled PPC ad rotation. There were no options, just a default “optimized” setting that displayed the ad with higher CTR...