Mahmoud Ahmadinejad

After his re-election in 2009, anti-government protesters used Twitter to help coordinate and organize the Green Movement, sometimes called the "Twitter revolution."

Iran's leaders responded by blocking access to Twitter, Facebook and other social media sites. Ordinary Iranian citizens still were able to access Twitter using illegal VPN software.

Mahmoud Ahmadinejad, Iran's president from 2005-2013, demanded in a letter that Obama overturn an April US Supreme Court ruling that allowed the seizure of $2 billion worth of Iranian assets to compensate victims of a 1983 terror attack.

In his entreaty, Ahmadinejad suggested Obama had failed to deliver on a promise to improve ties to Iran by allowing the court decision to stand.