Is emarketing moving too fast for books?

Next to my desk I have a stack of emarketing books that I've collected over the past few years. Anyone who wants to can drop by and borrow one. Sometimes a colleague will ask for a recommendation.

Two of my favorite books are The Long Tail by Chris Anderson, and Wikinomics by Don Tapscott and Anthony Williams. Both books are landmarks that fundamentally changed the way we think about marketing on the web. They're exhaustively researched, well-written and generally fascinating.

And I don't recommend either to my colleagues.

It's not because I want to keep them to myself. It's that both suffer from the curse of the great emarketing book: they were so good that they made themselves obsolete. To read either book today, for the first time, would seem like a waste. The reader would spend most of their time thinking "but everybody already knows this stuff!"

Keep in mind, both books are less than two years old. In two years, these titles went from being ground-breaking new ideas to generally accepted wisdom to "ho-hum, tell me something I don't know". In fact, both seem outdated today. Wikinomics because many of the sites it referenced have already come and gone, and The Long Tail because further research on the subject is already causing the theory to evolve.

Two years.

I thought that was ridiculously fast. Then I read Groudswell, by Charlene Li.

Groundswell, a guide to social marketing based on Li's research at Forrester, has been on the shelf for all of three months. And it already feels outdated in several spots.

For example, Li makes several mentions of a new micro-blogging platform called Twitter. New? In the time since the book was written, Twitter has been annointed the next great web success story, been plagued by well-publicized technical issues, been surpassed in buzz by sites like Plurk and Friendfeed, and risen from the ashes as a comeback story.

Which begs the question: is there even a point to reading books about social media trends and technologies? (For what its worth, books about human factors and usability have far more staying power. As Jakob Nielsen is fond of saying, technology changed quicky, human nature doesn't.)

Is it possible to write a book about what's happening today that won't seem like a hopeless relic by the time it rolls off the publisher's press? Can we still learn something from a book that we can't find in our favorite blogs? Or should I just clear off my book shelf and set up an RSS feed to Six Pixels instead?