I've been looking around for ideas and methods that I will be using to promote my website and I've been intrigued on how the backlink tiers work. Correct me if I am wrong, from what I could understand, I will be doing a 2 tier promoting (not sure if there is more tiers or how they are classified but would love to know more if u could), so it would work like this: MY SITE TIER1 like facebook, google plus, youtube ? that leads to my site ? TIER 2 blogs and related sites to post comments that leads and backup the TIER1 sites ? I know what PR is but I don't know what each number means, could some one clear that up for me ? PR0 to PR10 ? Like 0 means what and defines what ? Would love some guidance on how this works!