trillianjedi - 11:09 am on Jul 20, 2008 (gmt 0)

Toolebar PR is not a sign of authority. I actually thought twice about even mentioning toolbar PR in the post, but thought I would for completeness (and a few years ago it was a better guage of link popularity than it is now).

Authority comes from ranking and in particular for multiple phrases around a keyword. A site that ranks top 5 for multiple common searches around a keyword is, in my book (and in Googles in my experience), an authority around that keyword.