Engadget reported it, and Yahoo confirmed it…Yahoo’s displaying for a small test group the following message: "Uh oh... We are unable to display Yahoo Mail. Please disable Ad Blocker to continue using Yahoo mail." The original complainants were on Adblock/Adblock Plus Forums from folks who had to disable their adblockers to access their “free” email.
Yahoo isn’t trailblazing anything with this. It is something which is becoming more and more common…sites demanding disabling of adblockers to get to that site’s services…even The Washington Post.
So…just to let you know it’s coming…and there’s not too damned much one can do about it, either. As for disabling Java (to prevent infection through Java applets) – I haven’t seen any reports as to whether this will prevent getting your email…but it wouldn’t surprise me one bit…or byte.
Source:
http://www.engadget.com/2015/11/20/yahoo-ad-blocker-issue/