Navigational elements on a blog or any website are an important feature, but you should be careful not to take things to extremes which can hurt the progress of your site, both from a SEO perspective and for website conversion.
I benefit from being a top commenter on a number of blogs simply because I am consistently active on those sites, and I have gained the benefit without changing my commenting habits.
Some of my blogging friends are aware of the problems, but have opted to use such a plugin anyway – I fully respect that decision, but many make that decision “blindly” without being aware of the possible consequences.
When I did my round up of readers taking action of various kinds with seo, I missed out on one very active reader. I hadn’t been by his blog in a few days, and there has been quite a significant change.