Just as the second law of thermodynamics means that the universe trends toward disorder, so Godwin's law dictates that online discussions must trend toward Hitler.
This has been a common enough axiom on the web for a while, but now, we have some concrete figures to support the theory. Pseudonymous statistician Curious Gnu has compiled a database of Reddit threads covering some 4.6 million comments, and scanned them for mentions of the words "Hitler" or "Nazi." After removing history subreddits from the data, Gnu found that once a thread hit 101 comments there's roughly a 15 percent chance of a Hitler mention. But go over 1,000 comments and this probability skyrockets — to above 70 percent. Looking at all the data, Gnu concludes: "78% of Reddit Threads With 1,000+ Comments Mention Nazis."
However, as Gnu notes, this isn't a total vindication of Godwin's law. In its most common wording, the law specifies that there will be a comparison made to Hitler or the Nazis, and due to entirely understandable time constraints, Gnu's data does not account for the context these words appear in — only that they appear at all.
But really, how often do comment threads that bring up Hitler (excluding history discussions) do so without making a comparison of some sort? To suggest that this data doesn't offer support for Godwin's law just because it's not wholly context-aware would be an awfully strict response. Some might describe it as authoritarian, or... fascist.