During Argentina’s military dictatorship from 1976-83, over 30,000 “subversives” were disappeared by the government. As these disappearances began to occur, the mothers of the disappeared began to congregate around the Plaza de Mayo monument in front of the capitol building. Since they were suffering mothers, the military dictatorship found it more difficult to repress them as easily as they had with other points of opposition, but simply labeled them "locas" as an attempt to discredit their efforts.
These "Madres de la Plaza de Mayo" became a force for public diplomacy when they took advantage of the international media attention received by Argentina's hosting of the World Cup to draw attention to their cause.
It's interesting to see the paralells between Iranian and Argentine Mom Diplomacy efforts, from today's New York Times:
Ahead of a planned opposition rally on Monday, Iran tightened security and arrested over 20 mothers who were mourning children killed in the unrest that has broken out since the disputed June 12 elections. The mothers had taken part in an antigovernment protest in Leleh Park in central Tehran every Saturday since the death in June of Neda Agha-Soltan, the 26-year-old woman whose shooting became a symbol of the government’s violent repression.
Arresting protesting mothers who have recently lost their children is a sign of desperation from the Iranian government and cannot last for long. Just as the death of Neda has become a symbol of Iran's brutal repression, the defiance of Iranian mothers, outraged at the damages inflicted upon their sons and daughters will continue to communicate the tyranny of the Ahmadinejad regime to the rest of the world.
The Mothers of the Plaza de Mayo began only with their collective sorrow, their white kercheifs and determination to find out the truth. Their mediums of international communication were effectively more limited than those that exist today. I'd like to be the first person to start the "Mothers of Leleh Park" Facebook Group, but it's definitely not my place to do so. Hopefully an Iranian who recognizes the similarities between the two movements and the potential of Mom Diplomacy will go ahead with it.