My colleague and coauthor Julie Ask and I are watching with dismay as company after company shrinks its desktop website down to a small screen using responsive web design (RWD) techniques so it fits on – but isn’t optimized for – smartphones.

Companies have delightedly embraced responsive web design as the one-size-fits-all solution to mobile, tablet, and desktop sites. In a recent survey of digital business professionals, we found that 93% are using, piloting, or planning to pilot responsive web design.

That sounds great on paper. After all, RWD is a very practical approach to developing websites that render on any device. But when mobile tasks diverge from desktop tasks as they often do in commerce, the one-size-fits-all approach taken by most responsive retrofits will fail to delight or even satisfy customers on smartphones or desktops.

People do different things on their smartphones than on their desktops or tablets (see figure). To delight and serve your customers in their mobile moments of need, you need to give them exactly what they need to move forward in their immediate context. So if you can’t reach all customers with an app – AND YOU WON’T! – you will need to deliver an app-like mobile web experience.

But mobile moments were never your design goal with desktop browsing, and responsive techniques alone don’t magically fix that. More often than not, you must deliver a different experience on smartphones, one that is task-oriented, loads instantaneously, uses the available real estate wisely, works with one hand, and delivers service directly into the full context of a consumer’s mobile web moment.

To deliver great mobile moments on the web, you’ll have to take a page out of mobile app design to fundamentally rethink how you can deliver better mobile web experiences. Understand the needs and motivations your customers have on the go; design a great mobile experience; tune for performance and results; and use the full range of client-side and server-side web techniques – what we call a responsive+ approach – to deliver mobile web experiences that change based on a consumer’s context: location, preferences, habits, and situation.