Groundswell was written by two analysts from Forrester Research. Forrester occupies a unique position. They have access to the internet’s great thinkers through briefings that they have with all the leading web service companies: Yahoo!, Google, Facebook and everyone in between. On the other side they act as a marketing consultant to a number of big consumer brands.
Li and Bernoff have crystalised the lessons that Forrester Research learned walking both sides of the street in the Groundswell. The book does a good job of educating the average consumer on the so called web 2.0 services and how consumers interact with them. They also provide a helicopter view about how to approach incorporating social web techniques into their business.
The most valuable parts of the book are the anecdotes and case studies (some of which are from Forrester Research clients) which brings the concepts that they talk about to life. Their Social Technographics model provides a framework for segmenting audiences based on their level of interaction with web properties and communities seems to be built and expanded from the adoption model that Bradley Horowitz developed and circulated back when I was in Yahoo! as a key part of the social search strategy.
There is a blog supporting the book which can be read here. Li has since left Forrester Research to set up The Altimeter Group, you can read her new professional blog there as well. More book reviews here.