Re: Blog Commenting
Yes, blog commenting is an effective way that helps in SEO but they should be do follow otherwise they will not give any benefit to our website.
Re: Blog Commenting
Blog Commenting is one kind of the Linkbuiding method.Its a kind of the discussion.And it always helps you to advertise your products.From it you can also add the signature with your keywords for your website domain.So i can say its one of the website promotion method.
Re: Blog Commenting
No follow do not pass the link juice, they can get you the traffic though, back links have to be a mixture of both.