There’s really nothing here, except the Avenger’s logo and Sam Jackson as Nick Fury narrating. However, if I had to guess at the niblets of information, I’d say there’s a good chance we could see the Skrulls. And that would make me absolutely geek out.
And if I had to hope for any plot line, it would be this one:
The largest Skrull-related conflict involving Earth has been the Kree-Skrull War. The Kree Accuser Ronan had wrested control of the Kree Empire from the Supreme Intelligence and attacked the Skrulls, reigniting hostilities. The Avengers become involved once the Super Skrull kidnaps Captain Marvel, and in turn they battle a Kree Sentry robot, three of the original Skrulls that had fought the Fantastic Four, S.H.I.E.L.D. agents, rogue Inhumans and legions of Skrulls. The Supreme Intelligence ends the immediate conflict by revealing to Avengers’ ally Rick Jones that he has vast mental potential, which is then used to freeze all combatants in place. The Supreme Intelligence announces that, while the Kree and Skrulls have reached genetic dead ends, the human race displays incredible untapped potential. It was revealed years later that the conflict produced a Kree-Skrull hybrid, Hulkling, who is the child of one-time lovers Captain Marvel and the Skrull Princess Anelle.
But my guess, is, it may be more in line with this, since it seems to tie into Captain America’s WWII plotline a bit better:
The first alien shapeshifters introduced in the Ultimate Marvel Universe are known on Earth as the Chitauri, who financed the Nazi regime in an attempt to conquer the Earth. Their leader Herr Kleiser states that they are called by other names on various worlds, including the name “Skrull”. These Chitauri claim to originate in the “lower fourth dimension”, and assume others’ forms by devouring them; it is unknown what their true form looks like, since the only time one of them is shown in it is after it has been killed and dissected. The Chitauri have a hivelike social order, with the “officer caste” having superhuman strength, durability and high intelligence.
Of course, The Skrull invasion, is merely a guess. If you make an Avengers movie, the antagonist has to be epic. On a scale like no other. [via]