Weak SEO activity
This activity carries a low weighting in Search Engine Optimization. It may need to be carried out alongside other tasks in order to be fully effective. Read the text carefully for further details on how to do blog commenting for SEO for maximum impact
A link from Page A of Website A to page B of Website B carries more weight if both Page A and Page B are about the same topic. So finding a blog post on another site that is related to your content and being able to add you link in the comments section seems like link building heaven.
This easy way to build links was just too good to miss and it was jumped on. Programmers wrote scripts that could send robots to thousands of blogs and add comments like "Great info, visit my site at http://www.myspammysite.com/spammy-page.html.
Bloggers became over loaded with spammy comments and abandoned blogs became black holes sucking in robot generated content.
To discourage the spammers blogging platforms like WordPress automatically started marking links in comments 'no follow' (a signal to search engines that the link should not be taken as a ranking signal)
Search engines quickly worked out how to spot abandoned blogs by their endless spammy comments and discounted them as link farms.
Black Hat spammers still use software today or contract out the spamming of blog comments to companies mainly based in Asia. With low costs they can still submit tens of thousands of comments to blogs in the hope that one or two get through or that a particular blog still has 'do follow' links.
First you need to accept that 99% of all links in blog comments will be marked 'no follow' ... so why do it?
Good blog commenting is indirect SEO. The link in the comment doesn't affect your rankings but it brings a great deal of targeted traffic ... and some of those people may create links to your site that actually count.
To generate that traffic you'll need to create comments that show the link is worth following. That means sharing just enough knowledge to show you are an expert and provide the carrot that more worthwhile information lies beyond the link.
That takes time and resource but it can be highly effective. Someone I don't know posted a comment with a link to one of my books on a blog. The link is 'no-follow' but it brings in a steady flow of traffic and those people who arrive via the link are three times more likely to buy the book than general organic traffic ... see the pattern?
If its you that is doing the blog commenting you need to:
I'm Tim Hill, a Search Engine Optimisation and Online Marketing specialist. I created this site to help others understand that SEO is not a mysterious black art!.
If your a newbie try the Getting Started in SEO page, otherwise feel free to dig around and learn more.