1) How often does Google Update PR?
1a) Is it the same for all websites or not?
1b) If not, what matters? What are the factors influencing on that?
1) How often does Google Update PR?
I think it was 3 month but that is not the same anymore. Google is planing to take away the PR from the toolbar.
1a) Is it the same for all websites or not?
Yes it is but it was a small one some month ago where only some sites got the update.
1b) If not, what matters? What are the factors influencing on that?
Only google knows.
I think it is related to the number of the links to you website.
