How does commenting on a dofollow blog promote my Web site?
Most blog software creates a link to your Web site when you comment on a blog post. Links bring people to your site when they click the link, but each link can also count as a “vote” for your site with search engines. These votes increase your page rank and make your site appear closer to the top in search engine result pages. Dofollow blogs create normal links that count as a vote for your site.