Google announced on the AdWords blog that they will be changing how their ad rotation works, essentially preventing you from continuing to leave your ads on rotation after 30-days.

Google said:

Google said they are doing this because leaving the ad rotation on “can inhibit advertiser performance and deliver less relevant ads.”

The three ad rotation options include:

Optimize for clicks (default): Ads expected to provide more clicks are delivered more often into the ad auction than other ads in the ad group. These higher-quality ads gain more impressions than other ads in the ad group, resulting in higher ad-served percentages. By using this option, your ad group will likely receive more impressions and clicks overall, since higher-quality ads attain better positions and attract more user attention.
Optimize for conversions: Ads expected to provide more conversions are delivered more often into the ad auction than other ads in the ad group. This option optimizes for conversions, so it takes both clickthrough rate (CTR) and conversion rate into consideration. If there isn’t enough conversion data to determine which ad will provide the most conversions, ads will rotate using “Optimize for clicks” data. Although this option may result in your ad group receiving fewer clicks than the previous option, it will likely receive more conversions, which can result in an improved return on investment (ROI).
Rotate evenly: Currently, this option behaves as follows: Rotated ad serving delivers ads more evenly into the auction, even when one ad has a lower CTR than another. The impression statistics and ad-served percentages of the ads in the ad group will be more similar to each other than if you select one of the optimization options. However, these statistics still may differ from each other, as ad position can vary based on Quality Score.

Advertisers do not seem happy about losing this control. Here are two comments:

Forum discussion at WebmasterWorld.

Image credit to ShutterStock of colored clocks