John Cook says:
... I regularly update old rebuttals when new data is released or when new papers are published. In this case, I updated my original rebuttal of the "Antarctica is gaining ice" myth with the latest GRACE data from Velicogna 2009 and while I was at it, also incorporated references to a number of other papers, trying to give a broad overview of what the peer-reviewed science had to say about what was happening in Antarctica.
Fine. I see that. The original article was written in December 2007, but attracted no comments until March 2008, including the one from AnthonySG1, which first appears in the page capture in July 2008. A non-committal ("stay tuned") response from Skeptical Science was already in place. PaulM's comment came some months later at the start of September 2008 and was captured at the end of that month. However, there was no reply at this point.
Six months later, the article was rewritten, with its new focus on a distinct treatment for land and sea ice. Although no date appears to have been given for the rewrite, it was captured on 14 April 2009. At this point AnthonySG1's comment still had the original noncommittal response and PaulM was unanswered. This meant that Skeptical Science had an article that said that land ice was falling and sea ice was growing, but had two old comments that disputed an entirely different claim - that Antarctica was losing ice overall. The result was confusion: a comment in June 2009 told PaulM to chill out:
Chill, amigo (no pun intended).
The article makes the distinction right off the bat between land ice and sea ice. Your two links discuss SEA ICE. We know there's been an increase in sea ice.
It wasn't until January 2010 that the comment thread was adjusted. Here's John Cook's take on what happened.
When I posted the responses to those particular comments, I mistakenly thought they were comments to the updated post (SkS is a big site so I don't keep track of all the comments as they come in). So in responding to the commenters, thinking they hadn't read the updated article, I was unfair to them. It was an honest mistake but I'm a little annoyed with myself for making it because the focus on the timing of comments and responses distracts attention from the science discussed: Antarctic land ice is shrinking at an accelerating rate but Antarctic sea ice is increasing despite the fact that the Southern Ocean is warming faster than the rest of the world's oceans. This information is accurate, derived from peer-reviewed research, as SkS's main commitment is to maintain fidelity to the peer-reviewed literature.
I see two problems with this explanation. Firstly, not only were the comments not new, but the article was not new either. The comments were a year and a half old, and the article itself had been revised nearly a year earlier. I have cast my eye over the April 2008 2009 version of the article and the one at January 2010 and they don't appear to be materially different to me. Perhaps someone with more time than me can check this out in more detail.
The second problem is the suggestion that Cook erroneously thought the commenters hadn't read the article, forgetting he had rewritten it several months before. However, he did know that he had responded before - he could read what he had said to AnthonySG1 back in 2008. His explanation doesn't cover the question of what he was thinking about his earlier response. We are presumably asked to believe that he deleted it without thinking and inserted the new "erroneous" ones, ridiculing AnthonySG1 and PaulM.
It's a stretch, in my opinion.