Short answers, pulled from the story.
Super Street Fighter IV: Arcade Edition was first announced on the 4th of April 2010 by producer Yoshinori Ono. This announcement confirmed the existence of a new arcade version designed to redefine the fighting game landscape.
Super Street Fighter IV: Arcade Edition added twin brothers Yun and Yang from the Street Fighter III series as playable characters. The update also made Evil Ryu and Oni playable out of the box instead of keeping them as hidden bosses.
The console version of Super Street Fighter IV: Arcade Edition was released on the 7th of June 2011 for the Xbox 360 and PlayStation 3. Physical media for the game followed on the 28th of June 2011.
The Version 2014 patch released on the 30th of May 2014 switched the PC version of Super Street Fighter IV: Arcade Edition online services from Games for Windows Live to Steam servers. This update also introduced GUI improvements and a reworked achievement system.
Super Street Fighter IV: Arcade Edition sold 1.1 million units worldwide by September 2014. The game had previously sold 400,000 units worldwide by December 2011.