The extremely anodyne, and not quite accurate "usage" example given by the OED is: "correcting others' errors, especially online, can quickly lead to invocations of Godwin's law."

That is, it will lead to scolding the purists as "grammar Nazis." In that relatively mild?though all the more excessive?mold, we've recently seen those who compared Big Gulp soda bans to Nazi dictates shamed for violating Godwin's Law. And in the literary world there was that novel whose title was modeled on Hitler's Mein Kampf that aroused more wonder than outrage. What an innocent time that was just a few months ago.