David Smith, another alumni of our iPhone Studio, just released his latest iPhone app: AudioBookShelf. I immediately noticed the attractive interface, and the price point intrigued me. David graciously agreed to share his thoughts on not only iPhone app development, but also advertising, free vs. paid apps, and the rewards of listening to your users.

How did you get started developing applications for the iPhone?

Within a few weeks of the SDK first being released I started investigating developing for the iPhone. I had no previous experience developing for the Mac or iPhone. At the time I was a pretty advanced Ruby developer. I got started by reading the first few chapters of the Hillegass book, and then just started coding. I found the sample code projects provided by Apple to be a good starting point and, combined with a lot of experimentation, I got rolling pretty well.

My first app was (no surprise) a tip calculator. (I wonder if tip calculators are the new Hello World for iPhone?) I never actually submitted it, but used the experience to gain confidence. My first commercial project was called PerDiem FY09, which is a travel allowance reference for government travelers. This was pretty successful and was actually featured by Apple at one point.

With one success in the bag, I took the iPhone Studio class to take me from a level of knowing a way to do it to knowing THE BEST way to do it. This really helped me move away from a lot of the bad habits I had picked up being self taught.

Not long after attending the iPhone Studio, you released your first application: Audiobooks. It gives users free access to over 9,800 hours of audiobooks in the public domain taken from the LibriVox Project. How did you get the idea for this app?

I actually just stumbled across the LibriVox Project right around the time that I was looking for my next app idea. As soon as I saw it I knew that creating an app front end to this amazing repository of audiobooks would be a hit. I had seen a few text-based book apps in the store, but had always thought that the platform leant itself toward audio far more than it did to reading long-form text on such a small screen.

On the surface, creating this app seems straightforward. Using the AVFramework, it's fairly easy to play audio files on the iPhone. But Audiobooks is actually streaming the audio over the network and giving users playback controls. That's a bit trickier. How did you go about solving this?

Streaming was by far the trickiest part of developing this app. It had actually started as just being a download player, but we were required to switch this to streaming. This transition brought with it a much higher level of complexity, especially in dealing with keeping the user's bookmarks and handling networking interruptions. In the end, we were able to make it work mostly still relying on the AVFrameworks, with a few bits of "special sauce" mixed in.

As a free app, Audiobooks uses a unique advertising model. Can you share more about that?

When we first launched Audiobooks we thought about monetizing it by providing mass media advertising from one of the various providers (AdMob, Quattro Wireless, etc.). But the more we investigated these platforms the less we wanted to use them. We heard story after story of low fill rates, bad CPMs, and generally bad experiences.

So instead we decided to create a little web application that would serve our own advertisements. We had tried to sell these directly, but in the end we found that we made the most money instead by simply using this to promote our paid applications. This has helped us draw tens of thousands of ad views to our products at no out-of-pocket cost to us.

This cross-promotion has helped us turn the corner and make iPhone app development truly profitable. Audiobooks has well over 500k users, and grows by thousands a day. It is exposure that we could never afford to pay for.

So are you doing this full time now?

Yup, and actually a month ago I hired my first iPhone developer to help take some of the load off me. We do around $10-15k/month in revenue which is more than enough to create a sustainable business. We aren't one of those crazy stories of developers who make millions in a few months, but instead we have been profitable for almost a year now. We have really low costs and so far have been able to build a sustainable business model by keeping our costs low and our ideas fresh.

You also have a separate (paid) version of Audiobooks lets users download the audio content for offline playback. Apple recently started allowing free apps to use in-app purchase. In retrospect, would you have used in-app purchase to unlock this feature?

I suspect we will be adding in-app purchase to our free version, but probably still maintain the paid app. The App Store is all about exposure so I think having top 10 apps in both the Paid and Free lists is huge for us.

You recently released AudioBookShelf: a collection of hand-picked classics with a completely redesigned interface. What were the motivating factors behind the new app?

We had received a lot of feedback from our users that they like the concept of having thousands of audiobooks available to them, but found the discovery part of that intimidating. They asked us to curate the experience a bit and instead of giving them thousands of choices, do the leg work for them and pick the finest offerings and compile those into one app.

We then took that idea and expanded on it, upgrading both the audio and visual experience. We have edited and cleaned up the audio files to enhance the listening experience. We then went to work on making the visual interface much more attractive and accessible to a broad audience.

There's been a lot of talk about the race to the bottom in terms of pricing on the App Store. I'm glad to see you're bucking the trend by charging $9 for AudioBookShelf, although I'm sure it was a difficult decision. How did you eventually settle on a price?

There is undeniably a "race to the bottom" in the App Store. I'm not the kind of person who will complain about that. There is a lot of money to be made at $0.99 (in fact that is were we have made most of our money). The challenge really becomes in differentiation more than anything. We created AudioBookShelf to be different and better than our other Audiobook apps.

We felt that the app was most certainly worth $9, especially when you put that in the context of the broader audiobook market where even classic books often cost around $10 each. We also wanted to raise the bar for ourselves and there is something surprisingly different in your own mindset when working on something that you want to be worth more—I think you end up with something that is that much better.

I must say, the new interface and web site look amazing! You used some clever animations, as well. It's obvious that you focused a lot more on the aesthetics in this app than anything else. How did you go about redesigning the app?

The first thing we did was decide on a landscape orientation. This is very unusual for a book app, but we felt it made it feel more like a real bookshelf. Once we made that decision, the goal just became creating a user experience that closely matched the real world including a bookshelf you can browse, books you can pull off the shelf, and a player that looks like an open book. We think we really hit the mark in terms of visual appeal. The whole experience is very immersive and almost game-like.

We did all the animations with Core Animation which was a treat to use. It was really nice how just combining a few translations, rotations, and scalings can give such a strong visual appeal. The really tricky part with that was not over-doing it. Because Core Animation makes it so easy to make things move, it was tempting to get carried away and end up with a mess. Instead, we hoped to narrow the use of these kinds of things to make them almost unnoticed. They should hopefully just feel natural.

Did you hire an outside designer or do it yourself?

We hired a designer to do all the graphics in the app. There was no way a couple of engineers could give it the shine we wanted, so we found an artist who could. She did a really nice job of taking our concepts and creating polished UI elements for us.

Technically speaking, the integration was all done by splitting her Photoshop renderings into component PNGs and then styling the various UI elements accordingly.

Any hints as to what you're planning to work on next?

We are looking to expand both the quality and type of audiobook-related apps that we offer. This will include new partnerships with publishers to bring more "Best Sellers" titles to the App Store, rather than just the classics we have now.

Any advice for folks who have an idea for an iPhone app?

I would say that iPhone app development can definitely be thought of as a Gold Rush; there are a lot of players and a lot of money to be made. You'll be fine so long as you go into it with a sober mindset that it is hard work and a good amount of luck to become successful. I have heard all too often stories of people disappointed that their sweet idea didn't hit it big right away. It takes time, effort, and patience to win in the App Store (at least for 99.9%). But there is definitely a huge market here and lots of room still left in the store.

Thanks, David, and congrats on releasing AudioBookShelf!

You can check out AudioBookShelf in the App Store.

Ready to create your own iPhone application? Consider joining us in Long Beach in December for the next iPhone SDK Studio!