I'll start out by stating the obvious: Things go boom, transformers go transform, cameras go pan, people are orange and everything else is blue. Now, that being said, whoever does the final cuts for the trailers knows how to cut a trailer that is fun to watch...and most likely shows all the best parts from the movie.
This trailer doesn't really tell any story, but hey, what do you want? There was no story in the second one and barely a story in the first one, so there being no story in this movie really doesn't matter. I mean, what the hell do people go to see Michael Bay movies for anyway? To see orange people run from blue things that go boom! From what I deduce from the other trailers I've seen along with this one, is that at some point in the 60's during the moon landing (or before) some (or all) the transformers buried themselves (or crashed) on the moon. Now Optimus Prime is pissed because Marge Gunderson and the rest of the peoples on planet Earth didn't share everything they knew about his species with him. Then a bunch of transformers pop out of the moon and, as best I can tell, transport to Earth, possibly to the Washington Monument or something? Then they go all around destroying shit and probably chasing Sam Witwicky and his new piece of ass. That would be Rosie Huntington-something, a Victoria's Secret model with big boobs and big lips. Presumably they hope she will keep her face shut and not mouth off to the hand that feeds her. Let's hope that she either has a small number of lines or can actually act. She's a model, so let's not hold our breath.
Here's the trailer: