After Yahoo bought Tumblr, the company said that its adult and porn blogs would be left alone. But recently, Yahoo’s new adult blog search policy surfaced, which includes excluding adult blogs from Google, Bing, Yahoo, and other search engines. This has led to 10% of Tumblr’s user base becoming invisible and almost impossible to find.

With this new policy, Yahoo has removed around 12 million ‘adult’ marked blogs from Tumblr’s internal search. Tumblr’s category ‘Erotica’ has also been removed from the category index and the respective blogs will also be no longer indexed by Google.

Here is an excerpt from Tumblr’s new adult content policy:

Tumblr welcomes and encourages all forms of expression, but we have to be sensitive to the millions of readers and bloggers from different locations, cultures, and backgrounds with different points of view concerning mature or adult-oriented content. There are a lot of people in our community who would rather not see this stuff and could even get in trouble if they did.

• Blogs will not appear in Tumblr’s search and discovery features for logged-out users

• Blogs will not appear in Tumblr’s search and discovery features for logged-in users browsing in Safe Mode

• Blogs will only appear in Tumblr’s mobile search and discovery features for users who are already following you

As per Tumblr’s new rules, adult-rated blogs and their posts will no longer show up in tags. The only way to find a post from a blog marked adult–or to find and discover adult blogs–is to receive the link directly, such as if another user re-blogs a post, you are already following the blog, or you are sent a direct link.

This entire change has actually angered the Tumblr adult blog user community, since Tumblr has enabled robots.txt and inserted the rule (Disallow: /) that tells search engines not to search pages on all Tumblr adult blogs. Besides, the new policy prohibits all standards-compliant search engines from indexing the blogs, including Ask, AOL, Baidu, Bing and Yahoo.

Controversy and changing policies over adult content is not new as we saw a recent incident with the huge controversy over finding mature content on Twitter’s video-sharing app Vine–this was heightened when a clip of hardcore porn made it to Vine’s Editor’s Picks.

Although the video was removed immediately, the fact remains that people can still post nude videos or videos containing mature content. It’s not prohibited, as long as the video doesn’t violate Vine’s Terms of Service. Besides, Vine remains in App Store, though it’s not that easy to find anymore. Before, it was featured in the Social Networking category, but now, you actually have to go to the Search tab and type Vine into the search bar to see the app.