Dick Costolo, the CEO of Twitter, gave an excellent lecture last month at his alma mater, the University of Michigan. His theme was the way Twitter thinks about itself internally and the ways in which Twitter is interacting with and impacting on modern broadcast technologies. It is a clear lecture, wide-ranging and suggestive, with some good jokes (in his early career Costolo was a standup comedian).

Costolo starts with an historical analogy, comparing Twitter to the Greek agora. The agora … Keep Reading