This is known as a warrant canary and removing it in such an obvious manner indicates with a high degree of certainty that they’ve received a gag ordered request to comply with a National Security Letter.
This is the second public case of a warrant canary being tripped, the first being Apple in 2014. I hope this case brings more attention to NSLs and the ridiculously broad overreach of civil liberties that they entail. I hope at some point, the story eventually comes out and we learn what was so important that reddit had to be prevented from even speaking about it.
I was going to say didn’t that Oregon shooter say what he was about to do on Reddit, but then I looked it up and it was 4chan, I’m sure there are plenty of nutjobs on both.
The Government already subpoenaed reddit 44 times last year, of which, reddit complied 33 times. The NSL is different in that a) the range of powers it has is far broader than a subpoena and b) a NSL comes with a gag order that prevents disclosure to anyone about the contents of the order.
edit: Also, unlike subpoenas that require judicial review before being issued, NSLs are only ever seen by a judge if challenged by the recipient, after the fact. This wasn’t even a power recipients had until the law was legally challenged a few years ago.