The webmaster pagerank tool grades your pages as High, Medium, Low, or No PR. The tool shows them in a bargraph showing the percentage of pages in each category. In the last couple of days, mine has changed. Last week, all my pages, with the exception of about 1% that had no PR, were in the low category. I now have about 5% of my pages in the medium PR category, a lot of pages in the low PR category, and none in the No PR category. My question is: is this tool updated constantly, or does it only update on a set interval? My tool showed my pages' PR pretty much the same over the last 3-4 months. This is the first time I've seen a significant change.
FastWeb, google really love your site (just like your other thread). Google Webmaster mine here is often outdated (and many others experience too), check cache date of your site in webmaster tool and in actual, maybe your's is updated.