As you can see in this example, shared by Android Police, some users are now seeing this new pop-up appear when trying to watch YouTube content, which explains that in order to keep watching YouTube videos, users will have to disable their ad blocker, or make YouTube.com an exception within their ad blocking rules.
YouTube has confirmed that this is part of a new experiment, which has not been widely launched as yet, but could indicate the future direction of the app, in combating ad blockers to maximize promotional opportunities.
