There has been a lot of discussion about the recent trend towards flat design as opposed to the skeuomorphic approach that became so popular with iOS. Although the existing commentary on the topic has many valid points, I haven’t seen anyone discuss the more fundamental shift behind the visual flatness.

In practice, skeuomorphism is about thinking visual and interaction design in terms of metaphors. Skeuomorphic UIs have, almost by definition, a strong focus on the UI chrome. The focus on the chrome is not exclusive to skeuomorphism though. For instance, UI realism is on the same boat with the imitation of real-world textures and materials. So, how does flat design differ from that?

Windows Phone and Android are the most prominent mobile platforms currently adopting flat design. Here are some words by Mike Kruzeniski, former design lead for Windows Phone, from an interview published in The Mobile Frontier book:

One of the main concepts we focused on with both the Kin and Windows Mobile 7 was to create a truly content-driven interface. While the iPhone is beautiful, its UI and the UI of many other devices is built on the desktop metaphor. Most of the mobile interfaces we see in the market today are built upon entrenched metaphors inherited from the PC—folders, icons, desktop spaces, and chrome elements that are rendered to represent real materials.

On the Android side, here’s what their official design guidelines say under the Put Content Forward section:

Many apps focus on the content display. Avoid navigation-only screens and instead let people get to the meat of your app right away by making content the centerpiece of your start screen. Choose layouts that are visually engaging and appropriate for the data type and screen size.

Beyond the visual flatness, what both Windows Phone and Android have in common is their focus on content. The visual simplicity of flat design is an effective way of moving the focus from the UI chrome to the content.

In other words, the real deal about flat design—in my opinion anyway—is really about moving away from the traditional embellishing of UI metaphors torwards an all-digital content-driven approach to product design.