Author Steven Johnson, the founder of Outside.in, writes a lengthy treatment for Time Magazine on how Twitter is going to change everything. He's definitive and definitely positive.
He articulates a vision for Twitter that revamps journalism, advertising ad searching, all the while permitting end-user innovation to redesign the technology and its features. He is a little less forthcoming on the business model potential inherent in Twitter; indeed, he points out the beauty of its technology is that it might be easily replaced in a year or so.
The article is, not surprisingly, all over Twitter today on "How Twitter Will" searches.