Climb Aboard the Clue Train
It's also very prescient. It was written in 1999, but could very well be a contemporary work to "Groundswell" the groundbreaking social media book by Li and Bernoff (another book I highly recommend reading). Some of the references are obviously dated, but the main points are still relevant today.
I recommend giving it a read. It's easy to get through; written very conversationally. You can read it online at http://www.cluetrain.com/book/index.html or you can purchase a print copy on Amazon.
Disclaimer - The links to the books' Amazon pages are affiliate links.