All too often, I've wished the Google Toolbar's PageRank meter never existed. Site owners obsess over what it says, fixating on PR scores as if they are the end all be all. They aren't, as I've written before, such as in Google PageRank, Meet Yahoo Web Rank!
Now it's semi-official. The PageRank meter means nothing, according to Google's email support team. John Galt posted out on our forums being sent this recently:
The PageRank that is displayed in the Google Toolbar is for entertainment purposes only. Due to repeated attempts by hackers to access this data, Google updates the PageRank data very infrequently because is it not secure. On average, the PR that is displayed in the Google Toolbar is several months old.
There's more in the forum thread itself: Google says: Toolbar PageRank is for entertainment purposes only. However, the quote above is enough for a fun compare-and-contrast.
PageRank is for fun and often out-of-date? But what's Google telling searchers who enable it on the toolbar? Let's check the help page:
PageRank display - Gives an indication of the PageRank for the page you're currently viewing. PageRank is the importance Google assigns to a page based on an automatic calculation that factors in the link structure of the web and many other variables.
Time to amend that to say it's the importance Google thought of a page several months ago and in fact might mean nothing at all :)