The feature is called the Ad Review Center. Users can approve or disapprove of ads before they go into the feeds.
To do so, login to your AdSense account. Then look for the Ad Review Center in the 'Competitive Ad Filter' section under the 'AdSense Setup' tab. Choose the Client-ID starting with ca-feed-pub.
You'll have to put your ads on hold for 24 hours before you can filter through them. During that time, no ads will be served to your feeds, but afterwards you can go through the ad approval process.
The Original Search Marketing Event is Back!
SES Denver (Oct 16) offers an intense day of learning all the critical aspects of search engine optimization (SEO) and paid search advertising (PPC). The mission of SES remains the same as it did from the start - to help you master being found on search engines. Register today!