This article is written on one system – like all the other pieces and our newslinks – but a different system altogether hosts our comments. The first system is up (as usual) but the second seems to be down.
It was also not working for a long period on Tuesday. We tweeted apologies then but, since the problem is persisting, offer them now on the site too. We are working to get the problem resolved, and will report back as soon as we can.