Skip over the anecdotes, then most self-help business books are about 50 pages of text…

And the points they make are even less than that. I've worked places with a subscription to get abstract:

http://www.getabstract.com/

Very nice; you can just subscribe to the business books feeds, read the 3-page PDF summaries, and decide if you care to read any deeper.

I really liked Kindle's samples in this regard. Most of it is a few pages from the introduction, and most of the time that's very representative for the those types of books. If it starts with a recollection of the author's childhood or the experiences of a client, you can ditch it most of the time…

I was thinking the same thing, which in turn reminded me of the ultimate productivity blog (linked from Coding Horror):

http://productiveblog.tumblr.com/