Till yesterday my blog was PR4. I use the Firefox plugin SearchStatus to check the PR. Today it is showing PR7. But AFAIK, it's not the time for an update. Any clues?
normally when you switch between sites in Firefox, it shows PR of previous site before refreshing the PR to the current site.
You can use LIVE PAGERANK CHECKER. It tells the real PR of your site... Checking it's datacenters... Hope it helps...
you can check your PR here: http://livepr.raketforskning.com/ it would display your rankings w/ 72 DCs...