Here is the official proclamation of best practice in the eyes of Google
I am sure some of this post is going to blow people’s brains, though this is only the tip of the iceberg.
WordPress Comment Solutions
Shaun almost a month ago released a modified version of Lucia’s Linky Love that removes links from comments rather than nofollow them as a partial solution to Google’s changes to PageRank distribution in regards nofollow.
When Disqus first launched, I was a little critical because I like to maintain control of comments, give commenters the benefit of Dofollow links, and ultimately retain control of their user generated content.