Google On Blocking Banner Ads From Getting Indexed as Main Content
Google's John Mueller has answered a question about whether it is possible to block banner ads from Googlebot so they're not indexed as part of the main content.
In a Google Search Central hangout, Mueller said that there is no way to specifically block banner ads from being indexed. However, there are a few things that webmasters can do to make it less likely that banner ads will be indexed.
One thing that webmasters can do is to use the noindex meta tag on the banner ad. This will tell Googlebot not to index the ad. However, Mueller noted that this is not always effective, as Googlebot may still index the ad if it is deemed to be important content.
Another thing that webmasters can do is to use CSS to hide the banner ad from Googlebot. This can be done by setting the display: none property on the ad's CSS selector. However, Mueller noted that this is not always effective, as Googlebot may still be able to see the ad if it is rendered by the browser.
Ultimately, there is no foolproof way to prevent banner ads from being indexed by Googlebot. However, by using the techniques mentioned above, webmasters can make it less likely that banner ads will be indexed.
Here are some additional tips from Google on how to prevent banner ads from being indexed:
Use the noindex meta tag on the banner ad.
Hide the banner ad from Googlebot using CSS.
Make sure that the banner ad is not important content.
Use a content delivery network (CDN) to serve the banner ad.
Use a different domain for the banner ad.
By following these tips, webmasters can help to ensure that their banner ads are not indexed by Googlebot and do not affect their search engine ranking.