When Jared Spool mentioned this $300M button in another of his classic talks, he emphasized repeatedly how the metrics that determined the abysmal shopping cart completion rate were completely missing. Even though the metrics for how many people are exiting the flow via password reset and never coming back were relatively easy to get from the retailer's db, they had a flawed funnel model that they began with. They were only measuring between 'adding an item to the cart' and checking out. They had no metrics for 'request new password (reset)'.

This may all be dated now with very sophisticated client-side metrics but at the time it was relevant to the mega-retailer.