As much as you explain that toolbar PageRank does not show you a result that you can work with, people still tend to obsess about PageRank. Go ahead and read Danny's PageRank Guide once again. In any event, on Friday we reported about possible buggy PageRank but now there seems to be a wide update in the toolbar PageRank scores.
Most people are noticing a drop of one point, while some are noticing PR0s and others are noticing nothing.
Gabs at Search Engine Roundtable Forums asks if Google is capping the PageRank displayed in the toolbar by a certain value if your site falls within a specific category. Easy enough to check, but I highly doubt it.