Blog Feeds, or RSS (Really Simply Syndication or Rich Site Summary) Feeds are usually generated automatically by your Blog Backend (eg wordpress) and these feeds are basically a link and short synopsis of what your blog posting is about. These feeds can be submitted to indexing sites that provide a link back to your original article. For more information about RSS Feeds please see: http://www.rss-specifications.com/what-is-rss.htm For a list of top sites to submit your RSS Feed to please see: http://www.toprankblog.com/rss-blog-directories/
It’s one of the key features that allows blogs to easily distribute frequently updated content and amass huge followings. In fact, # of RSS subscriptions has become the measuring stick of success for blogs. As a blogger, you definitely want to maximize your RSS subscriber count to increase exposure and accumulate a loyal following of readers. If you’re new to blogging, be sure to sign up for a service called Feedburner (now owned by Google).
No link is entirely useless. There is value in blog commenting whether or not the blog is nofollow. The pessimists are so wrong about this.
Blog comment is useful for getting more traffic in your site which is helpful for earning money through adsense.But you can not find good back link by blog commenting because mostly blogs provides no follow facilities due to spamming.
There are few of many things that google tend to shows its softer side and one of those thing is blog commenting. Google algorithms that check on backlinks don't care where you're getting them from. That's is one of the flaw that can be used to kill competition. But then, de-ranking a website does involve the analysis of the matching niche and content quality of the donor website to your website... Blog commenting works wonders and blunders if not done correctly.. you should read more and experiment yourself.. its not hard.. only time consuming..
I think any link is useful, and there are sites that are not no follow but you have to really put time into it and make some quality valuable input in those comments you leave.
I get some great comments on my blogs..I also have to approve them before they go live, this way i catch the spam and either delete or moderate. Comment Links can be useful.. Specially on popular blogs. Good luck!
I would recommendGoogle Do follow Blog search .You can Search for relevant blogs and blog posts from a list of known Do Follow blogs.