Marvel Film Post-credits Scenes

At the end of all Marvel films, there is a scene after the credits.   Each one sets up the next film, or at least an aspect of it.

IRON MAN sets up THE AVENGERS.
THE INCREDIBLE HULK sets up, also, THE AVENGERS but as well as the bit in IM2 where he receives the telling off from Fury.  Or possibly IRON MAN 3 as Stark didn't know about the Avenger Initiative at the start of IM2.
THOR sets up, not to give too much away, THE AVENGERS and quite possibly CAPTAIN AMERICA.

So maybe I'm wrong.  Perhaps they are all there to set up THE AVENGERS.  If so, I think it's a good way to stir interest.  Though, as a nerd, I was already looking forwards to a Marvel film directed by Joss Whedon.