By Peter Ramsey at built for mars Take up for Netflix's ad-supported subscription was initially slow. The Wall Street Journal reported that only 9% of new signups opted for it, and of those who were happy to watch ads, 43% had downgraded from more expensive options. So Netflix made a simple design tweak: to 'hide' one of their most popular packages. The result: sign-ups to their ad-tier doubled. This case study demonstrates a masterclass of pricing psychology, and how simple changes (reliant on data and experimentation) can significantly alter the course of your product. Although before we start, I want to be clear about something: what you're about to see…