As you may know, scienceblogs.com is run on MoveableType 4 specially modified by SixApart for the site. The latest tweak was, apparently, a mistake, so the system was reverted to an older version (I have no idea what I am talking about, am I?) which makes posting and commenting painfully slow and likely to cause time-outs. The help is on the way, and the system should be fixed by the end of the week, so we hear.
If you post a comment and get a timeout, it is likely your comment has registered but will take a couple of minutes to show up. Save the text elsewhere (WordPad or such), click on Back, then Refresh the page a couple of times over a couple of minutes and, only if no comment appears, you should try posting it again. If I receive duplicates anyway, I will try to delete one of the copies.