Pirates of the Caribbean Teaser Trailer Analysis

This is a great example of a Teaser Trailer.

It's quite clear, the footage was made just for the trailer and the only shot from the movie is the close up on the skeleton foot. The film is based off the ride at Disney world (hard to believe it ended up such a success... at least the first one). However, unlike with books, the number of people who have actually riden the ride is much lower and the fact that probably most people wouldn't know it was based off it. Because its a Jerry Bruckheimer and Disney film, they can afford to announce who the actors are.
The narrative is hinted at but not made clear. All we learn is there is a possible curse. (Though that could be worked out from the title; Pirates of the Caribbean Curse of the Medallion