The important thing between desktop web and mobile that people don't seem to be talking about is that the users of each platform are fundamentally different. If you think about most apps that span desktop and mobile, one version tends to just be a smaller representation of the other. Yes we have things like responsive design and native development, but the design language for a lot of apps is nearly identical. My suggestion is that this is flawed design and flawed product management. It doesn't make any sense to translate the same design between platforms as disparate as web and mobile. There are many reasons why this is the case, but I like to boil it down to three major factors; Expectations, Information and Context.
After decades of using the web on desktops and almost a decade with access to smartphones, people have developed expectations of what is possible, desirable, fun and interesting on each platform. This comes in many different flavours whether it's expectations around user experience, design, imagery, text or more. On the web we tend to expect graphical or text rich applications that can give us a lot of information on one screen. Mobile users expect brevity and focus, with fluid and intuitive actions or gestures.
Different platforms have access to different information about their users. On the web you can set cookies and track sessions, gaining more information about your user as they visit your site. You can also understand what browser they are using, what their IP address is and what type of computer they are running. All of this can enable you to infer things about your customers, just like how Obritz famously price discriminated between Mac and PC users. Mobile takes this access to information far deeper. On mobile you can know the exact geographic location of the user, beyond that the tight integration of the mobile OS generally allows much easier access to the user's contact list, his or her social profiles on Facebook, Twitter, etc. even the images in their camera roll. Because of this disparity in information you will have to do more to learn about your users on the web, while on mobile you should be taking advantage of the ability to speak directly to your user.
The context in which the different platforms are used is wildly different. This may be the most important difference between the two. The nature of each platform suggests that mobile is far more intimate than the desktop web. We use our smartphones everywhere, in business settings, social settings, while we're watching TV on the couch or when we're in bed. Smartphones have access to us all the time, while desktops and laptops are used far more formally when the environment dictates their use is either convenient or productive. Think about the difference between a user that is sitting down to the laptop on their desk versus the one that is reading a funny story in bed before they fall asleep. These two users have far different needs when it comes to every aspect of the app that they are using, whether it's the need to be able to view the app on their smartphone horizontally or the fact that the desktop user is more likely to producing content while the bedtime smartphone user is almost definitely consuming content. Clearly context is everything.
What about the different mobile platforms?
This isn't just true between web and mobile this is also true between the different mobile platforms. Just as I gave the example above about price discrimination between Mac and PC users the whole Apple/Android Fanboy debates online should prove that the users of each mobile platform are fundamentally different with different needs and desires. I think it has been made clear in many places that the willingness to purchase apps or in-app items is vastly different between the platforms, but we don't recognize the more fundamental difference between the users of each platform often enough. This topic deserves it's own well thought explanation so I tackled it in my next post.