This is shocking news, I mean, we all knew PageRank was not something to look at too closely these days, but for Google to come out and say "The PageRank that is displayed in the Google Toolbar is for entertainment purposes only", kind of shocks me. I can not confirm this to be accurate, but a post at Search Engine Watch just a few minutes ago claims this to be the case. The member said that he emailed Google asking why a page's PageRank is zero and he got the following response from Google.
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. If the toolbar is showing a PR of zero, this is because the user is visiting a new URL that hasn't been updated in the last update. The PR that is displayed by the Google Toolbar is not the same PR that is used to rank the webpage results so there is no need to be concerned if your PR is displayed as zero. If a site is showing up in the search results, it doesn't not have a real PR of zero, the Toolbar is just out of date.
Apparently, Google is still using PageRank to rank sites but just not displaying the current value to the Google Toolbar user.