If an admin deletes a spam message, the message will still be visible in New Posts. But because I won't be able to see it, I can't remove it from the list.

This thread suddenly became hilarious.

Hello and bye to you, mister spambot. *WHAM*

@Jake: if you go to the main JCF page, you can double-click on the next to a board to mark all threads in it as read.

@ivo: hmm, that sounds like a good idea. I'm getting fed up of playing whack-a-spammer so I'll see if there's some way to improve the captcha.

As an addition to Torkell's statement and for those who haven't noticed yet, those who want to mark threads as "Read" but don't want to have specific "Unread" threads, there's a link at the bottom of the forums list that reads "Mark Forums Read", which of course will mark every thread as "Read".