I have to admit I am a novice in internet marketing and grateful to have found out about this site. I had been reading many posts, while I gain some knowledge, I was left a bit confused, perhaps someone can clarify my doubts for me. 1. Regarding backlink, I understand a high PR site is worth more than one with low PR. Does anyone what is the weightage like? Would be the minimum PR status should be considered for Sep purposes? 2. Why does edu, gov considered to be better for link building 3. do follow and no follow sites affect link building? if it does matter than which would be better. 4. twitter and Google have PR 10, but is it possible to get link from then? if yes the how can do it? 5. I have heard that some sites have gone from PR0 - PR4 overnight and some have rating drop from PR6 to PR2, I like to know why does this happen? Anyway to prevent rating from dropping? I am sorry if the above questions are too simple or even stupid but I an really at entry level in terms of internet marketing. I thank you for your patience.