Hi Isritter,
I don't want to sound like echoing everything that have been said here but I do agree with almost all of them.
Grafxextreme is rite when he said that no one could actually guarantee to have the 'secret' of big G.
Is it website age? Is it your unique contents? Or is it your backlinks?
Yes and no.
Yes because it's always best to combine all the techniques; optimize your internal and external backlinks and produce "relevant content". When I say relevant, it does not necessarily mean "unique". G's weakest link is dupe, so it won't hurt you when you submit the same content to different places, as long as the one at your site is produced earlier than the others.
No is the answer when it comes to decision made by G's algorithm. Thousands if not millions of webpages being produced everyday; can you imagine now what criteria is taken into account by G to decide on where to rank your page? Many of them. In short, if you apply everything, the possibility of your page to be ranked on top is higher than the rest.
The best way to understand (at least a small fraction!) how G works is to think of yourself as G. You saw two sites; oldsitedotcom is 2 years old and newsitedotcom is 3 months old. Oldsitecom received consistent backlinks everymonth from the day it was created but only about 30 to 50 backlinks a month. While the newsitedotcom received 1000 backlinks in the first month, 2000 in the 2nd month, and only 5 in the 3rd month.
So pls tell me G, which site would appear as at least far more legit to you?
-just-my-two-cents-