Blog commenting is the nicest method to interact with same minds. Though blog commenting you do not only express your views on other website but also earns valuable backlinks if content is relevant with your niche unless they are just useless words in eyes of Google. Blog commenting allows you to earn dozens of link in a link through investing your time and efforts to make informative comments on websites.
Besides it, blog commenting introduces your websites to other users who never find your website on net or are not in your circles. If the comment is good, informative and interesting for other peoples, it can generates traffic for site, though it takes time to be a blog commenting expert.