I'm a big believer that good product design is the difference between success and failure for consumer services. Great product design however, can produce even more powerful results.

I read about a fantastic example of this recently: Wallmart's pre-paid debit card enters users in a prize draw for every dollar that they set aside & save using the app. The prize is relatively small ($1,000 for first place and $25 for 499 runners up), but it taps into that human desire to win that already works so well with the lottery. Wallmart has published numbers on the volume of users of the pre-paid card and their average savings, so I've done the maths. This pool equates to at most 0.3% interest for everyone. While the actual value for consumers may be pretty small, the impact for Wallmart isn't, the number of savers is up 130% and the average savings per user are up 38%.

This combination of good product design, behavioural economics and an understanding of Wallmart's users is a great example of the power of product design to influence behaviour - and make a more valuable service as a result.