According to comic book writer Warren Ellis via Twitter, he said that there's another after credit scenes and Marvel did it again, I think its an open clue for the next movie -- Thor 2 , Captain America 2 and Avengers 2 movie, or maybe.... Ant Man movie.
check out the video featurette below to know more about the Extremis
Iron Man 3 now showing in all Philippine cinemas this April 24, 2013
SEE YOU ALL LATER AT THE MOVIES!
Marvel's Iron Man 3” is presented by Marvel Studios in association with Paramount Pictures and DMG Entertainment. Marvel Studios' President Kevin Feige is producing and Jon Favreau, Louis D'Esposito, Charles Newirth, Victoria Alonso, Stephen Broussard, Alan Fine, Stan Lee and Dan Mintz are executive producers. The film is distributed by Walt Disney Studios Motion Pictures.