My understanding is that if I have too many backlinks from low PR (pagerank) sites, Google considers them to be low quality links and if you have too many, your site may even be de-indexed from Google: http://www.seomoz.org/blog/how-to-check-which-links-can-harm-your-sites-rankings
I've read that some people say backlinks from high PR pages can be helpful to your site. But what about a backlink from a high PR site with a low PR page?
A lot of sites out there have higher PR, like Best of the Web directory. That is, the home page of Best of the Web has a PR of 6. But if you drill down to the specific page where a site is listed in the Best of the Web directory, the PR can be low (ie. PR of 0).
Does Google look at the PR of the overall site rather than the PR of the specific page when it determines how PR is passed to your site? Or does Google ONLY consider the PR of the specific page when it determines how PR is passed to your site?
If Google only considers the PR of the specific page, then it's not worth listing in a directory like Best of the Web because the actual page on Best of the Web that links to your site almost always has a low PR. In fact, listing on Best of the Web be harmful to your site because you're getting a backlink from a page with a low PR.