I am planning to build some MNS sites based on Adsense and/or amazon. What I want to know before starting, is which are the best methods to do seo for a mns? I am not planning to invest money in seo because i want to learn. I have a few ideas but i don't know how good are they. 1. Do-follow manual blog commnets 2. High pr article directoris with spinned articles from the original from the site 3. High pr web directories 4. Forum profiles Ideas?