What can you do in 30 seconds? Well, according to Instagram founder Kevin Systrom, one thing you can do is lose a potential user of your application. If your application doesn't grab the interest of a potential user in 30 seconds, they may move on. It’s the user experience that generates that crucial emotional reaction to your software, not the other pieces. No matter how cool your code is, no matter how fast your server-side logic is, if the user doesn't say "Wow!" in those crucial first seconds, your app will be sent to the back of the market queue. Remember that when you're deciding where to spend those development hours. That first impression is crucial.
I believe there are two parts to making that impression. The first is an emotional one: how “cool” is the interface? Does the application cause any kind of positive emotional reaction the first time it’s viewed? Let’s face it, when the iPhone first came out, the interweb was positively overloaded with reviews that had the words “cool” or “awesome” in them. Cool is hard to do, but when the design team pulls it off, life is good.
The second part is a bit more practical: can I do what I want with this app? Can I find out the time for the next bus, the score of the game last night or the current price of the Facebook stock without a lot of navigation, tapping or dragging? If not, I’m moving on to the next app or website.
The key here is that while your design has to be cool, it also has to be somewhat minimalist. Consider that old saying you've probably heard a million times: "less is more." There are few places where that is more true than when deciding what to display on the screen of your mobile device. With screens measuring only a few inches on the diagonal, you don't have a lot of room to mess around. The message your application is intending to convey has to be clear and the interactions concise. Getting rid of unnecessary steps to accomplish specific tasks is critical. Let your users get in, get what they need and get out again quickly while remaining impressed with the experience. Otherwise, the next time they need to check something quick, it might not be with your app.