Sometimes a picture really is worth a thousand words. We've all heard about the cyber-battle between the Iranian government and opposition protestors, with a flood of information coming from Twitter, Facebook, YouTube and other social media sources, despite the efforts of the authorities to block web access. But this image - in a blog by the security firm Arbor Networks - really tells the story of the Iranian regime's strategy:

"Any economic unit can emit money. The serious problem is to get it accepted" Hyman Minsky