Google has published the SafeSearch guide

It now has all the previously published information in one place.

SafeSearch automatically filters out adalt sites, offensive content, violence and violence in Google Search and Google Images.

Help documents explain how SafeSearch works. The information will help you understand if a search engine is filtering out your content, how to optimize your site for SafeSearch, and how to get rid of potential problems.

How do I know if there is a filter

• Enter the keyword phrase that caused the page to appear in your search engine, then enable SafeSearch to see if the page is still in position, or if it is gone.
• Use a site operator with SafeSearch running. If the web resource does not appear in the output, conclude that the search engine is blocking it.

Optimizing the site for “SafeSearch”

The above methods will allow the search robot to determine that some of the content on your pages can not be blocked.

1. Place a meta tag on pages that you think may contain something inappropriate:

<meta name=”rating” content=”adult” />.

This is best for sites which only have a very large number of pages with explicit content.

2. Make a separate resource for inappropriate content by adding metadata.

If your site is overflowing with questionable content but has safe content, Google recommends categorising it into groups. Let’s say put explicit content on a separate domain (subdomain) and add metadata:

explicit.example.com/page.html

Or in a separate subsection:

example.com/explicit/page.html

Without this, the search engine will consider all the content on the site to be explicit in nature and will start blocking it altogether in SafeSearch results.

You could name the subdomain or folder “explicit”, but this name is given as an example, you can choose any name you like. It is sufficient to group the dangerous content separately and mark it with a meta tag.

Further information

1. When you make the changes it will take up to three months for the algorithm to process them.
2. When blurring explicit images, the page may still be routed to a filter if the image can be blurred or is directed to an unblurred image.
3. if the site contains nudity, it may be filtered out regardless of what it is there for, although it may be a medical site.
4. Pages may also be filtered out because explicit images were posted by users, or because they were posted as user-generated content by hackers or through cloaking.
5. Remember that explicit content is not good for certain search engine functions. These include rich snippets, quick answers, and previews of video content.