Secondhand understandings are worth little.
Hagel et al would have better served their audience by getting out into the online world and seeing how it actually operates. It's one thing to read newspaper and magazine clippings and deduce a trend; it's another to experience the trend firsthand. Hagel et al definitely do NOT get online communities. Hiding behind a big consultancy's shingle does not confer understanding, empathy, or effective strategies for action -- that much is clear.