First came the film. Then came the trailer, stitching together the best bits of the film into a punchy two-minute short designed to whet appetites ahead of the film. Then came the teaser, packaging together a handful of shots from the trailer into a punchy yet slightly decontextualised one-minute short designed to whet appetites ahead of the trailer. And now there is the vignette.

This is the term by which the first promo for this summer's Looper has been dubbed by the iTunes trailer site. It's not really a trailer, and it's not really a teaser. So what exactly is it? Chances are you'll be seeing a lot more of these vignettes in the future, so let's take this opportunity to pick apart the Looper vignette to see what it can tell us about both the film and the medium ...

1) The Looper vignette opens with a brief introduction by director Rian Johnson. That's nothing new. Ever since trailers began debuting online, this has been a relatively common practice. Now that's out of the way, what happens next?

2) An establishing shot. To be specific, it's establishing - via the use of behind-the-scenes footage - that Looper is a film rather than, say, an album or a pair of shoes. So we're all clear. Let's see what Looper is actually about.

3) Fantastic. It stars Joseph Gordon-Levitt. Admittedly this shot is too brief to tell if he's firing a shotgun or a flame-thrower, but we know to expect: plenty of big-sky agricultural Americana. That's a start. What now?

4) Oh. More proof that Looper is a film, even though we already know that it's a film because we've met the director, seen the camera that the film was shot with and watched some of the film. Hopefully now we can get on with seeing what the film is about.

5) Except we can't, because now Johnson wants to introduce us to Gordon-Levitt, even though we already know that he's in Looper because we've seen a shot of him in it. But now all the introductions are out of the way, we can see some of the action that Looper has in store for us. Boy oh boy, this is going to be ...

6) No, sorry, wait. Rather than showing us any footage, Gordon-Levitt is going to sit in his weird deserted cinema and tell us what happens. And he's going to do it with his head cocked to one side, just to make things tricky for himself. Anyway, he tells us that in Looper he hunts down and kills his future self, played by Bruce Willis.

7) And here's a close-up of Willis's eyes, just in case you needed proof that Gordon-Levitt isn't just making up the plot as he goes along. Now, let's see what else Looper has in store.

8) Oh, for crying out loud! Now everything's come screeching to a halt so that Gordon-Levitt and Johnson can have a chummy playfight about how big and strong Willis is. Get a room, you two. A proper room, not this spooky abandoned cinema you both seem to live in. Honestly, all this wheel-spinning is really starting to nark me off.

9) Hang on. This is something. It's an explosion. A proper explosion, like you'd find in a normal trailer. Oh, thank God for that. We're back in familiar territory again. So now it must be time for the big finish ...

10) Or just Gordon-Levitt and Johnson back in their creepy private cinema, where they tell us that their film is quite good and that there'll be another dribble of information in three days. Whoopee. So that's what a vignette is: a fat dollop of nothing, presented by two blokes in a condemned cinema. Good to know.

Join me next week, where I'll be reviewing the next logical step of all this – a vignette for a teaser of an announcement of another vignette for a teaser of a trailer for The Smurfs 2. I can't wait.