Universal wants you to know that while Matt Damon isn't in The Bourne Legacy, his shadow hovers right over it. The movie's plot seems to grow directly out of the events of The Bourne Ultimatum, and the trailer features the actor's face briefly as well as a whole bunch of people saying 'Jason Bourne.'
But that's just the marketing stuff, I think. The trailer for The Bourne Legacy shows that the film might be an intriguing sidequel, a movie that takes place during the events of the last Bourne film as Treadstone falls apart and everybody tries to save their ass. That tangent should allow the series to continue in a really organic way moving forward, and I like the decision.
By the way, I know we've had this discussion before but I can't remember the answer - was Jason Bourne super powered? Because it turns out new hero Aaron Cross might be. At the very least he's been genetically modified, as we learn in this trailer. I'll hold judgment on that development until I see the film.