When used in conjunction with Webmail Ad Blocker the combo works on the old style yahoo email page.

Finally back to normal. Even side ad's are gone.

This is literally the "old" Yahoo mailbox. The new UI is terrible, and this beautiful person made this extension that gets around all that garbage. I wish I could hug you.

really helps cut all the useless fat yahoo wants to shove on us. works and looks smooth. :)