Actually it's called 'moderation', but I believe what you're referring to is 'censorship' which is the suppression of free speech.
Moderated comments have to be approved, for such thing to happen a moderator has to read them, if for some reason moderator does not have the time or patience to do so your comments will stay in limbo forever, or until someone does a clean up and delete everything.
Well, I know of two ways of moderation: or all messages have first to be approved, or all messages get posted until someone complains, at which point a moderator intervenes. This can be partly automatic, by tagging certain messages on length, on specific words, .... But no. I had comments pending, and others, on the same article, posted later, longer, shorter, posted directly. The funny thing was that those pending all had one specific aspect: they said that 1800 coins a day should be compared to the total daily traded volume.
(BTW, now, they have been released, 2 days later).
This is not the first time that I see this kind of systematic pending of comments on a certain subject.