At the end of April 2012, Google announced a big change to how your ads will appear in the search results. The change, which took effect at the beginning of May, has to do with the ad rotation settings.

The way it used to work is that you would select the "rotate evenly" option in the Advanced Settings category when testing 2 or more ads, and want them to display evenly over time rather than allowing Google to control which ads are displayed. While this "rotate evenly" option still exists, it will now only work for 30 days, after which Google will choose the best performing ad and begin to display that ad most prominently.

So the important question is, how will this change how you test your ads and run your account? Well, to start it will greatly limit the amount of data you can gather from any single test. By limiting the data to 30 days, this change makes it much harder to run long tests with ad copy. However, when ever you add a new ad to a ad group, you will now be able to turn the rotate evenly setting back on and test with the new ad. What do I think? I dislike this change to AdWords, I feel that it removes a useful feature for no reason. Whereas the recent changes to phrase and exact match are voluntary, and add more functionality to the platform, this change actually reduces functionality.

If you are currently running or managing paid search advertising through Google AdWords, it's now even more important to keep a closer eye on your ad's copy.