I realize most of us just don't have the time to get really involved and might only have time to leave a comment on a blog, but, if you do have extra time you can often learn by going back and reading the responses after yours and any comment from the author if they left one.
What do you expect to learn from your own comment?.
What can you learn about "the place" someone is in with their quit who's first post on the site was a comment after yours?
What do you learn about how the author took the comments so you can relate to them in their next blog?
I believe you can can click on the RSS feed link on the left of the blog and you will get an email notification when someone responds on the blog. Yes, the number of emails would definitely become overbearing for me.
Perhaps you could bookmark blogs of particular interest in your browser and then delete them after a few days? (You can make a folder for eX within your browser)
But perhaps on going back on a particular blog and seeing a first timer's comment, you could go to their page and try to give them some help or encouragement directly?
I realize it's work but quitting smoking is work and helping someone quit smoking is a work too. :-)