A post about comments on blogs that I have read on Joel's blog is quite interesting.

 

Since everyone can easily post on their own blogs, it makes a lot of sense to write a post on your blog and link to posts that inspired you or helped you when writing that post. This is a great way for raising quality of discussion and giving better visibility to blog posts that deserve it.

 

Quality of discussion shall raise simply because number of low quality comments shall decrease. Someone who makes a low quality anonymous comment presumably won't make a low quality post on their own blog.

 

Visibility of blog posts shall rise because of more people linking to them. Such posts shall have better page ranks and shall be more visible.