AdWordsAdvisor explains the possible reasons why ads may be showing on Google, but not on AOL.
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Rolfewinkler, if your ad is showing on Google but not on AOL, here are the most important factors to consider:
Have the ads been reviewed and approved? While your ads will appear on Google almost immediately, they will not be sent to AOL (or other partner sites for that matter) until after the ads have been reviewed and approved. As you might suspect, the time for an ad to complete the review process varies according to the volume of new and edited ads being submitted - with the highest volume typically occurring on Mondays.
Are your ads in the appropriate position on Google? AOL will show only the top four approved ads from Google. Each partner site chooses how many ads they will show, so this number will vary by partner.