Google has eliminated the limit to how many categories AdSense publishers can filter from their sites. There are 11 categories, and users can filter as many of them as they want.
"The category filtering feature allows you to prevent ads that fall into specific categories like 'religion' and 'dating' from appearing on your pages," says Arlene Lee of Google's Inside AdSense team. "You can filter categories by visiting your Ad Review Center, located under the AdSense Setup tab. Click the ‘change’ link to view available categories to filter. Your selections will be applied to ads in English, French, German, and Spanish, no matter how they’ve been targeted to your site."
"We also recommend taking a look at the columns showing how much of your recent revenue and ad impressions are generated by each of the categories," says Lee. "This will give you an idea how applying these filters may affect your account."
Previously, users could only filter up to 8 of the 11 categories, which include cosmetic procedures and surgery, dating, drugs and supplements, get rich quick, politics, religion, ringtones and downloadables, sexual and reproductive health, sexually suggestive, video games, and weight loss.
Google's doesn't guarantee that every related ad will be filtered, and recommends that users who see undesired ads block the individual ad or advertiser using the competitive ad filter or the blocking features in the Ad Review Center.