Apparently, the WhatsApp ban was reportedly announced by the country’s Committee for Determining Criminal Web Content, although it must be noted that the Iranian government does not support this particular decision since it intends to be seen by the people (and in a larger context, the world) as being far more progressive.
The more simple explanation would be that Facebook as well as Twitter being banned since 2009, it makes perfect logical sense then that WhatsApp, which is about to be fully acquired by Facebook, too, would be banned. Whispers on the street also have it that Iran is looking at launching their own internal online network, although that has not happened to date. Well, it can’t be fun to live in Iran at this moment if you happen to be in love with your social networks, right?