A WebmasterWorld thread asks a question most people who participate in search forums ask themselves. Does Google, on occasion, update the toolbar PageRank score of a particular web site between the major and mass toolbar PageRank updates we report?
Why do we ask this question? Well, if you visit enough forums, you are bound to see a thread or five with the title, "PageRank Update." These threads are fairly noticeable at DigitalPoint Forums but they are found at many other forums on a fairly recent basis.
Real Webmasters are noticing updates to their PageRank scores in the Google Toolbar. This happens all the time, and then they jump to the forums to be the first to announce the next PageRank update. But then you see a mass response of replies saying, "no PR update here."
So is it possible that what that Webmaster noticed was a true toolbar PageRank update for his site? Maybe. There are a few possibilities, the most likely is that he or she is hitting a different data center with different PageRank scores. But I would not rule it out that Google does push minor PageRank scores to the toolbar between major updates.
Forum discussion at WebmasterWorld.