Good link, i like the graph. As i've mentioned in previous comments, i'm not trying to impress, just inform. It maybe obvious to you what is needed to go up in page rank, but it wasn't obvious to me, so i did some research and now here I am!

Of course it's an exponential scale. Otherwise Facebook and Google would be 10, Twitter and major corporate sites would be 2 and the rest of us would all be 0.