Google's most recent update to the Toolbar PageRank shows they have made several adjustments since the prior update. Most people have noticed that some prominent link-sellers have had their PageRank reduced by several points. However, many small sites have also seen their PageRank scores fall by a point or more, which has led to a spate of postings by flustered webmasters wondering why they've been penalized.
It seems clear to me that Google has not only penalized link sellers, but they have also done another recalibration of the Toolbar PageRank display. It is well-known that Google's internal PageRank scoring system has far more levels of gradation than the simple 0-to-10 integer scale shown by the Toolbar. So, from time to time, it is necessary to recalibrate the relationship between their internal PageRank data and the Toolbar PageRank display to accomodate the never-ending growth of the World Wide Web. To put it simply, a site whose inbound links earned it a PageRank score of 4 in the previous update would find that those same links would only rate a PageRank score of 3 in this latest update. Multi-point PageRank drops for sites that did not sell links have been very rare, which usually indicates the original score was a borderline low and has now fallen below an additional threshold.
The upshot is that whole hosts of sites have seen their Toolbar PageRank score fall a little as these adjustments trickle down through the web. For sites that haven't bought or sold links, the actual impact on their search engine rankings has been zero because Google has long since incorporated these changes into the search results. Those who sell links have been complaining the loudest, of course, since they've been charging for links based on their PageRank scores. It will be some time before the link selling marketplace adjusts to this new reality.
