Ad rotation settings are a preference that determines the way your ads show in your ad group (if you have multiple ads). For example, you can have your best performing ads to appear more often or indicate that you want all your ads to be shown more evenly.
If you have multiple ads in an ad group, AdWords alternates the distribution of the ads you have selected.
The “Advanced Settings” section of the “Settings” tab of your campaign offers four different options:
- Optimize for clicks (default): This option shows more often the ads that generate the most clicks, based on your clickthrough rate (CTR). Google then tries to serve these ads more often than other ads in your ad group to help you save a lot of clicks and impressions.
- Optimize for conversions: This option shows the ads that are more likely to result in conversions (purchases or registrations, for example). Your ad group will accrue perhaps fewer clicks, but probably more conversions. If data conversion is not sufficient to identify the ad that can generate the greatest number of conversions, ads are served alternately optimized for clicks.
- Alternate regularly: the same priority is given to all active ads in your ad group, whatever their performance. Each ad is eligible to appear the same number of times. However, the actual number of impressions (the effective distribution rate) of each of the ads may vary, depending on a number of factors. If you select this option and if the ads in the ad group remain unchanged for 90 days, their rotation will automatically start to be optimized to increase the number of clicks or conversions. If you are using Conversion Optimizer or Enhanced CPC in your campaign, the ad rotation will be optimized for conversions. Otherwise, it will be optimized for clicks.
If you want to rotate your ads indefinitely, you can select the option “Alternate evenly” but indefinitely.
In the “ads” tab of your campaign, you can view the statistic “% served “, which tells you how often each ad has been shown comparing with the rest of the active ads of the same ad group.