Navin, how does Netflix make sure what your users’ expectations are and what part does design play in managing them?

Netflix is a subscription business so it's crucial that our customers have the right expectations when signing up, otherwise they would not choose to continue with the service from month to month. So our key business metrics like acquisition and retention allow us to know whether we are measuring up to our users' expectations.

Our signup flow is designed to communicate to users everything we believe will set the right expectations, and we are constantly testing new designs that will improve members’ expectations. Additionally, we offer a 1-month free trial to all new customers to allow them to judge for themselves. In practice, we've found that the experience of the free trial is what truly communicates what Netflix is and convinces people to continue as subscribers.

What are the biggest mistakes made in managing users’ expectations and how could those mistakes be avoided?

One of the biggest mistakes designers make when trying to manage users' expectations is to assume that people will read the text in their design. The fact is that most people do not read when they use a website or an app – they are constantly scanning, taking in only the biggest headlines and skipping body text.

The best way to avoid this is to make your designs as simple and self-evident as possible. This is not an easy task – in most cases this will require multiple rounds of design exploration and refinement. Users should not need instructions for how to use your product. There are exceptions of course, but I'm talking about mainstream consumer products.