The only thing that's new in this clip is the reveal in the last few seconds. Still, it's an entertaining bit of movie making. What JJ Abrams and director Matt Reeves have that is new is the 'This Is Actually Happening' camera technique. This differs from the 'You Are There' technique, most recently seen in 'The Bourne Ultimatum'. Actors in Cloverfield routinely spike the camera or behave in some other 'non-actorly' manner because it's not supposed to be a Hollywood movie, rather captured video of an actual event (which is happening right now). I don't think this approach has ever been taken before.
'The Blair Witch Project' differs in that its footage represents what an editor would have culled from a casual account of a camping trip after the video was discovered. That is, only the best parts of the video would have been used for the movie. Regular stuff would have been edited out.
In 'Cloverfield' the conceit is more complex. In this movie footage from a camera (or multiple cameras) is stitched together to present a realtime version of events. The difference between Cloverfield and Blair Witch is the editor for the Cloverfield footage is non-existent, whereas the editor for the Blair Witch footage was a real person who did their best to assemble the footage in the most compelling way. Blair Witch is then presented as if it were an edited version of the (discovered) video of an event which actually happened (instead of a Hollywood movie).
For Cloverfield the idea is that there is no editor (or producer or writer, or studio, etc), and the imagery is magically transported to the movie screen in your theater (and only your theater) as it is shot (in NYC) so you have a realtime account of a real event which is happening now. It's worth noting the storyline in Cloverfield takes place at night. [This is when most people go to the movies]. Having the action take place at night supports the feeling that the movie is taking place 'now'.
I know -- sounds stupid when you read it -- but this is the (subconscious) impression the audience is meant to have, and I think the strategy will work. Part of what will make 'Cloverfield' a success will be the visceral impact the movie will have because of the 'this-is-actually-happening (right now)' image-producing/editing approach. Word of mouth will be more effective than usual because people will infuse their description of the movie with the urgency of someone who actually lived through the events in the movie -- as opposed to the usual 'then, there was the part where they did such and such' spiel. Without knowing it people will describe this movie in the first-person, or with a first-person tone. And, without knowing it, the person they describe the movie to will sense that the person that is describing the movie to them had a great time (at the movie [which is being described]). And, that person (who has had the movie described to them) will want to see/experience the (events of the) movie (in the first-person) all the more.
It'll be both subtle and effective. Once again, hats off to JJ Abrams. He had a great concept for a shooting technique, produced a cool looking movie that everyone is talking about, and came up with one of the best marketing campaigns to date (and dumped it at the first sign it was getting on people's nerves). 'Cloverfield' is primed for success.