Barring the unforeseen, Iran's recent unrest will be smashed by the Mullahs, and I have to question the value of broadcasting oneself protesting in the streets to others who can't actually help you. I'm sure there is a value to that sort of communication, but in the protesting Iranian's case, I suggest there is a far higher value in the sort of communication that helps one actually win battles. I suppose a few hold a forlorn hope that America will come running to save the day, but we've never actually done that, despite often posturing in unhelpful ways. Just ask an Hungarian.
So communication is what's valuable and the value depends on context (and personal preferences). It may turn out that Twittering about your protest is about as valuable as Twittering about your lunch. Meanwhile, as the police fighting against you can testify, being able to call in for backup when an angry crowd is on your hands, is distinctly more valuable than lunch. Guns are also quite valuable in these cases. Might I suggest some Twitterphile might do us all a great service by drawing the analogy between decentralized communication (which is awesome despite my skeptical tone in this post) and decentralized weaponry? The situation would be much different if every Iranian had 140 bullets and the appropriate bullet firing mechanisms. Perhaps they could even use Twitter coordinate fire (though voice communication may be more apropos).
Unfortunately, the Irainians seem quite modern, asking "where's my vote" instead of "where's my gun" and assuming that being in the media=success.
As for the rest of the Twittersphere- look it's an interface to communication composed largely of a silly rule to facilitate text-messaging. Interfaces come and go, what's important is the underlying infrastructure. The actual, physical stuff in the ground- the first thing an enemy attacks when he doesn't want you to be able to communicate. That's what we've got to be worried about and we've got to be worried about it here, because our government's relationship to our elections is very similar to Iran's relationship to it's elections.