They are building a watchtower from which they can see the entire relm of Minecraftia. They're always watching you, waiting until you turn your back so they can sneak up behind you and attempt to steal your diamonds.
They're aliens. They almost look like greys (cliche alien type), they hate water (alien cliche), the end looks like a small planet (small planet= tall creatures evolving on it)
you see them out of the corner of your eyes...
they hate the rain...
they take your dirt...
but what do they do with it?
I think it'd be really kind of cool to discover the Endermen are building "Something" with those stolen blocks..
Stone(well dirt) henges etc... what do you all think
"Shall I craft you a ladder to help you off that high horse now?"