Should I Write A Book?

I have been talking to a couple of publishers about writing a book but have been feeling very unsure about it. David Maister in this post puts his finger on why:

I think it will be much more effective for professionals to bypass books from now on and make their thoughts and theories available purely through the internet.

In today’s world, it makes no sense to take nine months, on average, to get your material together and the same amount of time again (amazingly) to get it through the process of publication. Then begins the complicated business of marketing the book and by that time, the thoughts contained in the book are largely historic. By the time you’re in print, the odds are high that someone else has already put similar thoughts into play online."