Levels of spam in the comments seem to have exploded over the last week or two so I've been forced to put on comment checking. This means that when you first write a comment you have to enter your email address, I then check it and your email address is approved form then on, so you don't have to have a comment approved more than once (as long as you enter the same email on the comment form each time). This means that new commenters may have to wait a while for their comment to appear, but hopefully it will put a stop to the spam.