He's not talking about email notifications, he's talking about the "Show New Replies to Your Posts" page.
You've no idea how often I've wished I could remove a thread that has gone downhill or lost my interest from that page. In theory *I* can do it by using Mjödnir to remove all posts I made in that thread, but that would be an egregious abuse of my power, a pain in the ass to the other mods, probably not allowed, and might not even work.
(Before anyone asks, I won't do it for anyone else either.)