Perky, since you are a member of AR and know how things work there, can you perhaps enlighten me a bit about the zeal for commenting going on there?
Doug, I'm sorry but I didn't see this post until today!

The main reason that people got started on the blog comments thing was for google juice - it was perceived that blogs with more content (i.e., relevant comments) would rank higher and for a longer period of time than posts without comments.
Beyond that though, the real reason that many of us comment is simply for the same reason that I come here - to interact with one another. Commenting on someone's blog on a regular basis enables you to build a relationship with the blogger and others who may be commenting.
With some blogs you will see a familiarity among the participants and with the author - they all got to know each other on ActiveRain. It was never meant to be purely a blog platform like Wordpress or Blogger - but a network, a gathering place to get to know one another and build your own referral networks.
The blog you linked to above is one of the most helpful authors on Active Rain. I 've learned a lot from her and I have chatted with her via email as well. If I have a customer in that part of Florida you bet she'd get my referral - she knows her stuff and she seems to be a very nice person as well as honest and conscientious.
On the flip side there are bloggers on there who would never get my referral - they are either arrogant and puffed up with self importance, or all they do is post mindless copy-paste crap like recipies and Innman News articles.
I have friends who are in Hawaii, Houston TX, Connecticut, Florida, Louisiana, South Carolina, West Virginia....
The SMART blog comments (ones that go beyond "Nice post!") are important - not necessarily to get more customers but to build friendships and future referral partners.
This of course is just my opinion.