placing comments on blog articles is good when you have something of value to offer. The reader will be further engaged, informed or educated about the topic. The process should be looked at social influenceas one of building social influence, rather than one of link building. Developing a relationship with particular websites and making regular contributions via comments in blog articles will have a better effect on your social influence than getting a backlink. You must also keep in mind that many influential sites that allow blog comments have “rel-nofollow” attributes assigned to them. So, you would get no SEO credit for the backlink anyway.
placing a link in a blog comment does nothing and you should get nothing out of it if that’s all you bring to the table. Writing comments like, “Wow, great article you really nailed this one, link,” also serves no purpose for the reader. If you sell Pink Dresses and place links on websites that deal in Nuclear Fusion or Casino Gambling, why should you get credit for this when it has nothing to do with Pink Dresses?