I’ve been thinking about the comment policy for my blogs. I have started deleting comments when people subscribe to comments and use fake email addresses (I get the bounces and it’s annoying).
Also I am deleting comments that don’t make much sense or which don’t address the topic of a post. Some people seem to search for blog posts marginally related to a topic that they want to vent about.
I’ve had someone request that a comment be removed because it was written by someone with the same name as him (see this post if you want to read the details ). I’ve written a short document about unique names on the Internet  on my documents blog, hopefully it will be useful for other people who become concerned when they discover that they don’t have a unique name.
My general policy about comments is probably going to be not to delete them unless requested by the author of the comment (if there is a good reason), and otherwise to only delete them for technical reasons or for being wildly off-topic.
One thing that seems missing from most blog ethics documents is a section on comments. When I write my own code of blog ethics I’ll have to write a section about this. Suggestions are welcome.