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They mean drawing inspiration from the competition by taking a strong stance about what they're doing wrong; make their approach your enemy: http://gettingreal.37signals.com/ch02_Have_an_Enemy.php

It's probably a variation on 'opinionated software,' if I had to guess.

They mean you should read the book to find out. Making bold and outlandish claims is a typical way to get people to look at your product.