Yes it is useful to get backlink if you comment in dofollow blog and direct traffic if they click your link.
In my own point of view, blog commenting are good as a source of traffic. Well, it can also be a source of backlink but we are all aware that MOST of the blog are in NO FOLLOW.
Yeah, Its right you can get backlink from blog commenting. But maximum sites point out the submitted link as nofollow. Does anybody know how to collect the sites which will point out my site as dofollow? Thank you.
Blog is moderated by the owner. They usually reject those comments especially if your blog is related to their blog. So if your going to deal with this process you should have a relevant comments.
To feel how blog commenting works and its effect on your site, you should be posting relevantly and as much as possible in a related blog. if you do these, you gain three things = backlinks, traffic, and friends!
Blog commenting is great for backlinking...of course. However, if you remain visible enough with your comments and give meaningful, unique posts, you can also brand yourself as an expert within your niche. People will begin to notice your name and your knowledge and start to make connections.
Blog commenting is for specific backlinking to a particular blog post. That will create quality back links. So use your blog post url instead of your blog url.
Blog Commenting helps in getting back links.Check this website for more information. http://www.seohosting.com/blog/link-strategies/effective-blog-commenting-to-increase-page-rank/
This is very useful, but it has rules, you must write on dofollow blog in your niche and you have to write interesting comment and there will be more chance to get traffic with backlink
Google likes sites that are regularly renewed and updated and everytime a comment is posted on your blog, it counts an update... In other words, comments keep your site fresh...
There are programs out there if you google for them But i wouldnt trust half of them, theyprobably just send spam everywhere
Official Google blog says that blog commenting will be useless. Google officially announced that they will consider most of comments as spam - http://googlewebmastercentral.blogspot.com/2009/11/hard-facts-about-comment-spam.html