[the web] google page ranking

This Google page rank thingy has me puzzled. The ones you’d expect to be up there are up there – the Worstalls, Dales, Pollards, Voxes and so on and the ones you’d expect to be nowhere, such as yours truly, are nowhere. That's understood. Interesting that, from my sidebar, Norman Geras was the most widely read site and two who hardly ever post were both running at about 30%. One of these can be understood because of the quality of his occasional pieces and because he's always commenting on other sites but the other is a puzzle. And the one whose rank I simply can't understand is a high-quality blogger whom I know has many comments and yet the site registers zero on the Google Bar. How can that be?