I was recently hit by a mass comment spammer, leaving 21 comments on old entries in my blog, and so I have been forced to make one change to my comment policy: All discussions will now close automatically one week after an entry is created.
If you want to know how, there is a “script at Geeksblog”:http://backlog.geeksblog.com/t/2003/02/23/000065/ that’ll automatically close comments for entries older than a specified age. The script only works for MySQL-installations of Movable Type.
*Update:* I am not the only one plagued by mass comment spamming, as evident in “this BBC article”:http://news.bbc.co.uk/1/hi/technology/3210623.stm.
I am also making one more change to my comment posting policy: If a comment itself is on-topic for the subject being discussed, but the URL is suspected to be spam, the comment may be kept, but the URL deleted.