Since the book is a collection of essays on various topics, there is no single set of conclusions to be drawn, but the editor barfs up a stew of random bits:

Primarily, it's dangerous to write a "history" of an evolving phenomenon. While we can make observations and draw conclusions, it's a bit premature, and things could yet take a turn. However, the medium is so widespread, and interest in it so central to culture, that some effort should be made to record "history in progress."