I spent two very pleasant evenings and a reasonable morning reading this 300 page book.
As a consultant who is about to do just that: measure the impact of an intranet web site for a large international company I was of course very interested (and critical) of what the authors have to say.
The book breaks down into three parts:
Part I: Measurement Strategy and Planning
Part II: Measurements and Consolidation
Part III: Analysis and Action
I found part I to be a very useful overview and framework for developing a measurement strategy.
In particular, the many sets of questions that the authors list are a great help in exposing elements of a strategy.
Parts II and III were (for me at least) less informative in that they were more based on common sense and many of the statements made there were all too easy too derive from part I. This is not as bad as it seems however for Part I covers almost half of the book and this part alone provides more than enough value to cover the cost of the book. In any case they were interesting enough that I read through the entire book (which says a lot).
While the book is a good start it is by no means the be all and end all (and considering the rapid flux of the field I don't think the authors ever had this pretention). In particular, my interest lies in the impact of intranets and this issue is covered almost as an afterthought in the very last chapter which is a pity considering that probably over 80% of all web development currently takes place on intranets.
An indepth discussion on impact measures related to knowledge management and sharing, workgroup collaboration and culture transformation would all be highly useful additions in a possible second edition. From the costing point of view, cost lowering metrics of websites such as self-maintainance and self-regulation as well as extensive support for self-publication (i.e. without intervention of "traditonal" webmasters might be a useful addition.
Nevertheless currently this book is a must read for anyone in the field involved with website justification.