If Google no longer update the PR,then they should stop the PR check function, because there is no update PR value be shown any more,then it is unfair for those growthing sites to sell AD ,you know ,PR still a inportant reference for most of advertisers.
Being that Google has denounced the selling of links I doubt that they will have sympathy for sites that are unable to sell ads links due to a low pagerank
It appears that G is doing the PR update on the fly now instead of one big world wide update as in the past. Also, every site we manage, has not received a major update. My advice is work on detecting and fixing any page you have that is a GrayBar and don't worry about anything else. Good topics to look into are:absolute vs. relitive linking, canonical issues and SE friendly navigation. Also, use your copyright notice on each page to absolute link back to the domain. This guarentees that there is a Page Rank feedback loop in place for the calculation.