I don't know what Twitter really is at this moment, but I joined it and made my address (http://twitter.com/AkioKobayashi)
Is it interesting? Is it useful? I don't have any idea. But I heard that many people against the vote in Iran have used it. And, recetly, my company's young staff are trying to use it for their business. Maybe this new media? or tool? has much possibility.
