Johannes Beus
You can now find sites that offer a PageRank-indicator for your own homepage a dime a dozen. They will promise nearly everything from “more visitors for free” to “better rankings” and because many webmasters trusted these promises and integrated these notifications on their own websites, the people who provided these services saw an increase in PageRank as well of linkpopularity of their own sites. Some of them then turned around and used this to sell links from these domains or host sites that were optimized for profitable searchqueries. It seems that Google started to notice this behavior now, the ranking-charts.de
PageRank is in turmoil and some forum-users are reporting that the PageRank of other such sites are not stable anymore either.