I am now often blogwalking to get more backlinks and to get traffic. I am very surprised because of really many blogs are getting high pagerank. I think this fact because Google have been changed their policy about how to handle nofollow comments. Google are now counting nofollow comments and give commentators points, this is different with older policy that Google didn't count nofollow comments.
I recommend you to read a good article from Daniel Scoco in Google Changed How It Handles Nofollow (And How It Might Affect Blogs)
