A guide to weblog comments

Excerpt:

Stay on topic.

Bloggers enable comments on specific blog posts to hear more about the content of the post. Don’t change the subject. There’s nothing more annoying than seeing a comment on a post about Hurricane Katrina that reads, “By the way, do you know anything about turtles?”

Contribute new information to the discussion.

Twelve people saying the same exact thing in one comment thread is useless and irritating. Before you comment, read the entire thread and make sure your comment offers something new to the conversation. If you don’t have the time or patience to read an entire thread, then don’t comment at all. The longer a comment thread the more likely someone has already said what you’re thinking, and the less likely it is to be read by future visitors anyway.

Read the whole article, it’s worth it.