So it would seem that one of my sites NoSlang.com recently got hit by the so called Canonical URL bug.
Some of you may remember a while ago when MSN was posting a PageRank of 2? This wasn’t a mean Google joke, it was a case of people linking to both http://www.msn.com AND http://msn.com (without the www).
Since it’s possible (although a bad idea) to actually have 2 different sites on those urls, Googlebot got confused and thought it was 2 different sites with the same content. Thus, the pagerank of the www suffered, and the non-www was seen as a new site (so no pagerank).
This happened to Noslang.com in that it’s main page had a 0 pagerank (unless you went to /index.php of the non-www then it had a 3), but all the sub pages had a pagerank of 5.