Stealth banning is pretty devious, in that to the banned user it doesn’t look like there is anything wrong or out of the ordinary in terms of their normal interactions with the site, but in actuality all of their interactions with the site are completely hidden from all other users, meaning that to the rest of the world the banned user simply doesn’t exist.
Reddit has a fairly strict code of conduct, or reddiquette if you like, meaning that actions like stealth-banning or even outright banning is quite a normal occurrence, and it isn’t all that unusual to find yourself on the wrong side of the ban hammer, or their zealous spam filter for that matter, a couple of times during your reddit tenure.
Of course the nature of a stealth ban means that you won’t ever know that you have been banned, though luckily there does exist a nifty little trick that you can use to check if you suspect that your account might have been banned (in other words, there is no activity on any of your posts or comments, no matter how “troll bait” they might be).
Individual user accounts are accessible at http://www.reddit.com/user/USERNAME. If you are logged in, hit your user URL. Everything check out okay? Right, now time to check as to whether or not you have been stealth banned.
Log out of reddit. Hit that same user URL. If you are served a 404 error page, I’m afraid it is official.
You’ve been stealth banned.
And now you know.