Great article. I wasn't sure where it would be going in the beginning but the conclusion is right on point.
As a startup one should measure "everything" that they can. Website visits, where they click on the website, do they even get to a sign up/login page? Same goes for the product. Which features do people use? How often do they use it? Do people sign up but never use the product?
This will be much more valuable than just asking customers.