A pattern seems to be developing: Thursday morning, Mark Ruffalo shared via Twitter an "Avengers: Age of Ultron" poster giving his character, the Hulk, the solo spotlight. This follows Robert Downey Jr. debuting an Iron Man character poster a day earlier. So those looking for the next reveal from the upcoming Marvel Studios sequel likely should keep an eye on the Twitter accounts of Chris Evans or Jeremy Renner (fellow core Avengers members Scarlett Johansson and Chris Hemsworth are both sans Twitter accounts).
Also, don't forget that with Downey's poster reveal on Wednesday, he also promised a "big announcement" that should hit on Thursday, March 5. What that is remains unrevealed, though it's sparked plenty of speculation.
Written and directed by Joss Whedon, "Avengers: Age of Ultron" is scheduled for release on May 1.