There's a network of Dutch subreddits, 99% of which are managed by the same clique of mods. Recently I noticed comments I had posted in those subs over the last few months had completely been ignored. It turns out I have been shadowbanned, and not just on the primary /r/thenetherlands sub, but on every single one of the communities they manage. There is no apparent reason for them to have done this to me. My messages…
I was under the impression that shadowbanning was a moderation technique reserved for the admins, and unavailable to subreddit moderators; IIRC, it also applied to the entire website.
So it's not a true shadowban, but any posts you make on subreddits who have shitlisted you will get deleted instantly.
And of course when a post of yours is deleted on reddit by a mod, reddit does not tell you this or indicate it to you in any way.