Strange blog commenting behaviour

[#1]

I've just tried to submit a second blog comment to this article, but the comment's not appeared. I have experienced cases in the past where I'm told a comment needs to be moderated, but the important bit there is ‘I'm told’ – there was no message to that effect this time; the comment simply didn't appear, with no explanation for why it didn't. When I tried re-posting it though I did get a message saying it looked like I'd already posted that comment. So, err, what's happened?

[#2]

Have you ever posted two comments to any previous article - I'm wondering if there is a one comment per person restriction.

[#3]

I can't say for certain either way, but considering that the Community's been running for a while now, and that I used to comment on EOD posts etc. fairly frequently, I would imagine I have commented more than once on a single post before.