Probably the best way to do that is to do it yourself. If you look at the upper left hand of the node, it will tell what date the node was created by the person who wrote it. It also tells the time as well :-)

Offhand, i can't see any reason why you would want to do this, since if you want to know when a node was created, you can just look at it. It's usually good to look at nodes anyway, unless you're here just to be a troll (which i'm assuming you're not since you seem interested in trying to better the site)

HTH,
jynx