Is it possible to buy or sell something using Bitcoin, in an offline mode?
In other words, if I had my wallet on my mobile phone and I wanted to send or receive money from another Bitcoin user who also has their wallet on a mobile phone, can we send/receive bitcoins offline to each other and then later re-sync the transaction to the network?
I find offline mode critical for this currency to progress beyond a simple crypto-currency experiment because relying on the network means that if network access is unavailable, your wallet is useless.