Recently it has been observed that Google is using inaccurate information regarding PagePank. When the Google PR is shown on our toolbar the PR is significantly lower than on Google’s Directory. This affects everyone using the Google toolbar, as Google needs to address this problem immediately. This causes a lot of trouble for people performing Search Engine Optimization and looking to find good advertising space.
Hopefully this will be resolved soon so nobody gets to confused and loses some valuable advertising space and money. It is still unclear which PR to follow, but for now I recommend using Google’s Directory PageRank.