The smell of the mail

I have never quite understood why things in the mail have this weird smell that other paper products do not. It's not even a nice smell but it seems to be on all the leaflets, pamphlets and the occasional envelope.

Does it smell like that at the place where these things are printed? Do people get turned on by that smell? Does smelling it make the smeller instantly feel like buying whatever junk they're offering? Is there a jungle somewhere in the world where all the trees smell like that? Hmm... ...