Have you noticed PR Updates, I have seen some blog posting and social media site updates that their PR increased, well for this blog it is still PR3, PR ( Page Rank ) is only needed if you would like to sell links because most of the link buyers are PR hungry. They believed that PR is one of the big factors in SEO ( Search Engine Optimization ) , which I disagree.
So How important is page rank for you ? Do you notice increase in traffic after increase in Page Rank ?
You can check your PR Here
See Facebook Communication regarding topic