Looks like 90% of organic adult traffic is shifted towards big porn tubes. The pie left is so little for the rest of adult websites.
Of course, not to mention so many keywords that are no longer showing adult results. I have a very big database of adult keywords collected, since I work for many years in the industry.
Now when I check some of them (big keys) it shows fully non adult. And this is not about English only, it's same in other countries as well (Germany, Italy etc.)
This shift started for about 6 months, so I think it's here to stay. We must remember that Google is here to make more profits, user's experience is on 2d place. Bing is light years away in market share.
Maybe it's time for surfers to realize Google is no longer relevant for adult searches. Unless there are big tubes in first searches, you will get some circle jerk content which is from same tubes (or redirection to them).
I search for amateur porn and what do I get on first page? Twitter page which is a pure spam one.
AMATEUR PORN (@WoWSwingers) | Twitter
https://twitter.com/wowswingers
There are many other results complete junk. So as a surfer, you have 3 options: go straight to tubes and search within it OR waste a lot of time searching through forest OR use different search engine.