I started my daddy blog about five months ago. Like most new sites, my site was placed in Google's sandbox. My page rank was zero for the first four months. Then just like that, my page rank went from zero to six at the end of September. Actually, my page rank alternates between zero and six because the new page rank has not propogated to all of Google's data centers.
I am happy with my new page rank, but I think it's strange it went from zero to six. What happened to one through five? It seems like my page rank should have been one after the first month, then two, then three, and so on to six. Why does it go directly from zero to six?
The answer is that my page rank didn't actually go directly from zero to six. The PageRank value you see in your Google toolbar is only a snap shot of the actual value. Google only updates their toolbar every few months. Internally, PageRank is computed continuously. Not only is the value computed continously, the value isn't limited to integers. For instance, my PageRank of 6 could actually be 5.64, 5.90, 6.12, or 6.4164.
If you want to read more about PageRank, take a look at Matt Cutts' blog.

