It's probably just the Google Dance (PageRank) update still going on and if you follow your PageRank I'm sure you have noticed this too - but doesn't it seem that PageRank is dynamic now rather than static in-between updates?
I notice when I wake up in the morning here in Australia PageRank is lower across the board and then throughout the day if fluctuates. It's usually at it's peak when I go to bed.
Could this mean that PageRank is changing based on live data rather than remaining static even though the underlying values it represents are constantly changing? Would this be a good thing?
For the link sellers it would have an impact but I don't think it would be that drastic. Instead of stating you have a PageRank of X to potential link buyers you say your PageRank fluctuates between X and Y. It would also provide more meaningful statistics as you could tell when your site was rising in Google as the PageRank rises on a more current basis.
I'm fairly certain it will calm down and settle like usual. When Google plays with PageRank, just like when it was offline for nearly a month last year, all kinds of speculation goes on. It shows despite that fact that we shouldn't pay too much attention to PageRank it really has an impact on us Webmasters. We love to talk about it and we just can't help but chase that little green bar.
