A/B testing: a comprehensive guide to getting started

I found the section about why more companies for do A/B testing particularly interesting. It's true, when outside marketing firms suggest something like A/B testing to executives, they get upset. They wonder, "Why should we devote engineering time/resources to some testing scheme? Isn't that what we hired you to do?" This is one of the problems with making marketing and engineering too modular and not supporting enough communication between the two.