Hahaha... nobody knows? just kidding right? If google don't know it, how can they update it. I think google webmaster have calculated when is the most effective time to update PR. They aren't updating PR just because they want to. I believe they will chose the right time.
There are two types of page rank. One that we normally see and use is called "Pseudo Page Rank". This is the one that is publicly available form google in tool bars or through other sites that use the google approved code to track page rank. This page rank is updated in approximately 3 months. It could be earlier or late as to the liking of google guys. The actual page rank is how ever only available with google and changes dynamically. No other body on earth knows the real PR value. This can be any thing like 3.124 or 2.789 not necessary a whole number like 3 out or 10. When there is a google PR update this decimal values may be rounded up and exported for public use. Again the rules of rounding is not available with anyone except Google.
Internally, it's done constantly. Externally (as in the toolbar), whenever they feel like. There's no set schedule. There's no point in worrying about PR anyway. It's a minor ranking factor at best.
Having learned much here, but I also want to know how long does the update keep? 1 day, 2 days....or 1 week?
I've tried looking for information on google dance schedules myself, and found a couple of online websites. One site mentioned that if you typed in your keywords and the results were showing up differently on these 3: .google 2.google 3.google all preceding with www and ending with dot com of course that most likely the google dance was going on. I've not real way to verify that.
i think google clasifiend into 2 class, first. update minor, it chose one by one from google analytic. secon update major. all of you must warn about it. coz my pr 3 was washed by uncle google. hiks hiks hiks... im so sad... my poor blogs
It can be one month, or two months, or more. Google hasn't been very regular with PR updates these days.
It can be one month, or two months, or more. Google hasn't been very regular with PR updates these days.