The Guardian has changed its user-generated comment system – moving from a client-side system to a server-side one. (This story was first published here, where you can read a bit more of the background.)
With the new system, the comments are just part of the web page, like all the rest of the text.
This is a great change by the Guardian, and not before time. Google has already started to index the text of comments, as this search for some text I left as a comment once shows.
If you notice any problems, they’ve asked you to point them out.