We have spent a lot of virtual ink on examining the utility of Twitter as a business tool--especially for small business and marketers.  But it is impossible not to lose sight of the adoption of Twitter as an overall tool for communication, especially with events across North Africa and the Middle East, where several key social media sites have been vital to pro-democracy protesters' ability to organize mass demonstrations.  In an interview with Terry Gross of WHYY and NPR's Fresh Air, Twitter co-founder Biz Stone shares his amazement at how important and widespread the microblogging service has become.  He addresses events in Egypt, as well as rumors of Twitter's multi-billion-dollar evaluation and possible purchasers: