When Google begins it's monthly (roughly) PR and BL (backlink) update, SEO's anxiously watch the toolbar to see if their PR changes (hopefully for the better). However, since the update propogates across the datacenters, sometimes slowly, this can be an agonizing process to observe. The solution? A fabulous tool at WebmasterBrain shows you the PR across all datacenters. During a non-update period, they will all be the same, but during an update, you can see your new PR on other datacenters long before you might see it on your toolbar. Great stuff!