I once submitted a link from my blog to Reddit. It didn't complain, but the submission wasn't viewed by anybody, being totally absent from Reddit and I was able to see the submission only if I was logged in.

I then talked to the moderators about it and they said that my link submission history contained multiple items from my blog, so the automatic spam filtering kicked-in, with my domain being blacklisted. Because the submission was good and ontopic, one moderator proceeded to whitelist my domain again.

I don't know if the key for this silent ban was just the domain name or the combination of (username, domain name), but it was a silent ban.

That isn't a shadowban. That's just the regular spam filter. A shadow ban is a slightly different approach. A shadowbanned user, when logged in can see his posts and comments as if they were there normally, but only he can see them. Other users don't even know about the existence of them. (Mods can see shadowbanned user comments and posts in their subreddits, but normally don't approve them because each post/comment has to be approved manually.)

Yeah, but I was able to see my submission while logged in, as if nothing happened.