I had a problem with SPAM comments some time ago. After trying a few defence mechanisms I finally settled on forcing people to log in. Recently I saw a revival of the SPAM comments. Of course this time I know the identity of the people leaving the stupid comments. I would threaten to leave junk comments upon their blogs - but this would not deter them (they might welcome the extra traffic).
At the moment I am deleting the SPAM comments shortly after they are left, but if the problem doesn't go away I might be forced to introduce comment moderation.
As they say It is an ill wind that blows no good. While I was deleting the SPAM comments I noticed that my home weather station has been off line since 14th of August. Hopefully I will be bringing it back on line again soon.