PR is thought to be a logarithmic function by many so that means that each step up in PR is worth x log.

So if log base is 3 say (complete guess) PR1 = 3 PR2 = 9 and PR3 = 27 on up to PR10 which is a huge number. If log base were 5 each step would be five times the previuos value with same result - PR10 is huge number. All values are devalued by damping factor and outgoing links of course. As I understand the algo!

And as incredible said above the link has to be relevant anyway!!