I've seen people saying that the Google sandbox does not exist. I say this is both true and untrue. I have seen my site appear in the google index in as little as a week, however there are portions of googles searches which I believe are way behind current. Let me give you some examples.
I have a Christmas site
http://christmas.gocurious.com
I started developing this site, probably in October 2006. Google shows 9 backlinks to this site (as seen by going to advanced search and choosing links.
I have another site
http://mma.gocurious.com
I started developing this site, slightly afterwards.
Google shows 2 backlinks to this site (same method).
Here's the rub. I have recently written 10+ MMA related articles. These articles at minimum should be worth 1 backlink each (however, they are distributed to multiple article sites, so maybe more).
So, I go to one of my competitors sites (although competitor is not correct...they are Christmas sites, aren't they). Anyway doing a link search on that site yielded 43 backlinks, most of them internal. I know my site also has these internal links, but they aren't showing up.
Conclusion1: The backlinks and links shown currently were harvested sometime in early November, a full 3 months prior to the pagerank update. So, if you are wondering how old the data is which is being used for the current pageranks, it is 3 months old. This is just an educated guess, but probably correct.
Conclusion2: Assuming I am correct with #1, then the next pagerank (perhaps April or May) should show a dramatic increase in backlinks for both sites, but my MMA site should go through the roof.
OR
For some reason, Google is not seeing the real backlinks to my site as existing...yikes! Or most/all of these article directories are blocking outbound links...I prefer to use the stale data theory.
Note: This does not mean that google uses old data for search engine rankings or search results. I know they index my MMA site (at least the main page) about every week or two.
So, if you are thinking about setting up a web site and you have a target date to reach pagerank or full SEO, you'd better start 6 months in advance. Start by putting up your root page, then get your linking done (either by article marketing, buying links or smart link trading). Then add relevant meaningful content. Of course everyone else will tell you to build up the content on your site first and perhaps they are correct...what do I know? Not much, but I am learning!