This one is tough, and I believe only google knows the answer, but from your experience: When google updates the pagerank, and I have let's say only one pr7 backlink and only one pr0 backlink, results pr4 for my site. When google updates the PR, and my 2 backlinks go pr8 respectively pr4, will my pr increase or the old pr (that is in their database) is taken in consideration (the pr is calculated before the update)? I'm asking this because I think it will take huge amounts of processing power to calculate dynamically the pr because all the websites pr moves, resulting in constant and never ending recalculation.
With so many trillions of web pages, for me is obvious that not all PRs can be calculated on same day (even same week). IMO millions of internal PRs are being updated daily. Each 3 or 4 months Google export those internal PRs to external PRs, and that's what most people call Google Update, but really is a Google Export.
Google's PageRank calculations are based on complex iterations. Pages on the internet are interconnected. Page A maybe linked to Page B, which may be linked to Page C ...this is a never ending chain and many links in this chain link back to A. Change of A's PR affects B's PR, which in turn affects C's PR... which in turn again affects A's PR. Thus PR of page A is a function of itself and has no 100% correct value. Google keeps doing this iterations on continuous basis. Therefore PR values are constantly changing. The toolbar PR that we see is just a representation of the actual PR on a log scale. I am not sure when exactly is the toolbar PR calculated, but my guess is it is done 2-3 weeks before it is updated at the data centers.
Beside, I just saw that an 'average' is there when it's time to calculate PR. I had one PR7 link to my site. Result: PR6 So I put it on directories with PR0 in the inner pages. Result: more PR0 I have, lower is my PR. So I manage to cancel my links to keep only the PR7. Result: PR6 again!!
Thanks malcolm1 and sachin410, REP. added. @w3bmaster - I don't care about my pr, I care about my backlinks and their backlinks and so on. But I was curios about this chicken-egg never ending question. Codythebest - thanks for your answer too. Interesting experiment about pr. But I am the kind of person that thinks that a link is a link and it's welcome.
You must practice link saturation optimization, watch the PR toolbar every 2-3 months and then follow these stats in order to see your true PR. If you have over 20 links from PR4+ sites, then your site will have a PR of 3+. If you have a link from a PR of 7, then your PR will become 4/5, depending on the volume of links you have. Only Google knows the true answers. The best way to increase this PR is through link-building, baiting as well as patience through extended periods of time. We may want to study the algorithms, but the simplest explanation is 2 months per update with data being changed constantly and the more unique site you have with unique content and much content, the larger your PR will grow and the more authoritative your site will become. More links = higher PR (this can be multiplied by getting links from high PR'd sites)
Different directories, so I assume different IP. These directories were PR3-PR5, however, when you submit your link in the inner page, it's most of the time a PR0. Also, they were in categories, so not sitewide...
On the next PR update I will get a conclusion and I will post-it here to inform everyone of my experience.
Yeah normally the updation process takes one or two weeks maximum. Because once i bought a link from pr5 site and after 3 weeks google updated page ranks..and fortunatly google catched that pr5 link..so i don't think its a continues process!!!
Only google can answer that bro, but I think its a continous process. we need to wait till next update which would be some time this month end.
To sell links on these pages and to get links from a symilar PR page. It's easier to get a link from a valuable website if you have the same (great) PR.