This article has good information, however, one little wrinkle. Leaving comments on blogs does indeed create inbound links. However, most blogs add a NOFOLLOW tag to those links. So, while commenting on a blog might interest HUMANS reading your comment (and that is the most valuable thing), it likely won't help you a whole bunch with search engine rankings. NOFOLLOW was developed by search engines so that site owners could tell them essentially "I can't vouch for this link, so don't pass any search engine rankings though it." Since most site owners can't vouch for links left in comments....the add NOFOLLOW (me included), after all I don't want to pass any link juice to home-mortage-for-you-1234.com......