Good article, though I think you should differentiate between types of 'walkthroughs.' I think the point is that you want the users to start using the application as quickly as possible without being hindered by a walkthrough. On the other hand it is important to teach users to use your application... and constraining yourself to commonly used functionality is dangerous. I find that it works very well to 'show' users by helping them do tasks right away (a walkthrough) instead of 'telling' them how to use the application and then leaving them to remember it (also a walkthrough).
How much of this marketing for an ebook do you think applies for a conventional book launch through a publisher? I guess that question also applies to any other tangible product for that matter?
Me-too products become exceptional and differentiable when they are build better (i.e. with more taste) and the focus is put on the customer's experience. Since ideas are just multipliers (thank you Derek Sivers), it makes sense to master the execution of an idea on one you know people will buy.