What's not to understand?
For each of your pages... the
PR value is almost completely dependent upon links pointing to your site, reduced, to some degree, by the total number of links to other sites on that page. Thus, a link to your site will have the highest amount of impact on your
PR if the page linking to yours has a high
PR itself and the total number of links on that page is low, ideally, just the one link to your site.
The actual formula (well, an approximate one, according to Google's official papers) for
PR is:
PR(A) = (1-d) + d (
PR(T1)/C(T1) + ... +
PR(Tn)/C(Tn))
where pages T1...Tn all point to page A. The parameter d is a damping factor which can be set between 0 and 1. Google usually sets d to 0.85. C(T) is defined as the number of links going out of page T.
Thus, a site with a high
PR but a large number of outbound links can nullify its own impact on your
PR. To increase your Page Rank, get as many links to your site from pages with a high
PR and a low number of total links. Hope that sheds some light ;)
NeO1