Re: Where are the Avengers?
They're busy people. Odds are, Cap will be on a mission, probably dealing with the Winter Soldier, while all the Mandarin crap is going on and won't find out about it until after it's over. And Thor is in Asgard dealing with a war with the Dark Elves.
The only real odd one out is The Hulk, as mentioned. Bruce and Tony kind of have a bromance going on by the end of Avengers and it's not like The Hulk has his own movie coming out full of plot or that he's particularly known for doing stuff besides keeping a low profile when not Avenging.
But then again, for obvious reasons Banner does like extended periods of time without a lot of contact with the outside world. He might have gone Doctors Without Borders-ing somewhere without internet.
The world does not work the way you think it does: