Blog comments can help with the search engine optimization of your website by seriously improving your ranking within the major search engines. commenting is still a reliable way to improve rankings when done correctly. It should be one link per comment and must be on a related blog or website. A mix of no-follows and do-follows is also important when commenting and it will seem more natural. Another SEO benefit from blog comments is that every time you leave a comment, the blog owner takes notice of you. This is especially true for repeat visitors, so it is worth returning to the same blogs over and over. The other bloggers will undoubtedly visit your website.
Blog commenting has been massively abused by spammers thus 99% of all blogs are comment moderated.
Best practice is to give valueable feedback to the article.
Using tools to mass comment blogs only gives you short term shady seo benefits and next to no traffic.
High traffic blogs are carefully moderated so if you cannot add a valueable comment you`ll never get in.
For internet marketing it`s about networking and building a relationship with partnered sites.