There's a battle raging for control of your phone, and it's not about what brand of phone, or what operating system it runs on, or what network it's connected to. This one is about the software that brands used to reach you, and the value they can add to your everyday connected life - of which your mobile is a cornerstone.

If you're a marketer looking to get into your customers' mobile world, you have a big choice ahead. Either, you can build a mobile app (like the ones in the iTunes Store or Android Market) or a mobile site (much like a normal website, but with a look and feel suitable for smaller formats). You can do both, and many big brands will, but for most budget will dictate that you choose one or the other. 

I've been on the fence for some time on this. Apps have been around for a long time, mostly in the form of Java games built with the JavaME stack. But the high fragmentation of devices has made these difficult to download to your phone, difficult to install, and difficult to find once they had been installed. A lot of that changed with the introduction of the iPhone and the corresponding apps that are part of the iTunes Store. Applications were not only simple to purchase, install and find, but for the most part good looking and easy to use. Google followed on this success and introduced the similar Android Marketplace. The stats below show just how successful this approach has been:

App Store
No. Apps: 300,000+
No. Downloads: 7,000,000,000+

Marketplace
No. Apps: 100,000+
No. Downloads: 1,000,000,000+

 Source: Wikipedia

If you've used one of these platforms, you'll probably agree they represent a step change from any mobile experience a brand could create before. Apps are not only easy to install - they are reusable, responsive and look great too. However, its not all rosy.

It's essential in business and software that a platform evolves, and it's also true that if your upgrade process requires customer intervention you will have fragmentation as different people upgrade at different times (or never - see IE6).  This is increasingly affecting the iOS and Android platforms, as what was once a single release has turned into not only an appreciable division amongst operating system versions, but in the different capabilities of the phones themselves to support them.

It's not a simple problem to solve, and the feature war in the mobile market will only see challenges increase. Combined with this, Nokia, RIM and others have decided to go it alone with their own platforms offering similar functionality but an entirely different programming environment and stack to support, which means different development teams with different skills. In other words, to target the majority cross-section of any mobile market you will have to develop the same app several times over, incurring cost and risk on each platform. For most, that's just not practical, and even if it could be done, you will almost certainly still exclude a large percentage of mobile users, particularly those with older phones.

Enter the mobile website. It has two great advantages over apps, namely:

1. Development - The number of developers who can build web applications dwarfs that of mobile app developers, and with some additional training and software these web developers can build mobile websites as well. The development language is tried and tested HTML/CSS/Javascript, combined with whatever server-side language is most appropriate. This brings down build and maintenance costs significantly.

2. Deployment - Upgrades are automatic and instant, so version fragmentation doesn't exist. Furthermore, apart from browser compatibility differences (around which there is significant documentation and software support) you get to develop for a common platform - the Web. Many phones can display browser bookmarks like apps, so the experience of finding and launching a mobile site is identical.

Of course, there is a downside, and that downside is the reduced capability of a browser to use the features of the phone to full advantage. However, those disadvantages are shrinking as HTML5 becomes better supported and features such as geolocation and local storage become common denominators.

If you doubt the ability of a mobile site to compete with an app, consider the case of Youtube on a iPhone. The iPhone comes with a Youtube app pre-installed, created by Apple, which does a passable job of searching for and viewing video. However, earlier this year Google relaunched YouTube Mobile, which offers not only much deeper integration with the site and better quality video, but a more usable interface.

If you still doubt, check out the video - 

Added to all this is the consideration that ultimately you'll reach more customers with a site - those without smartphones in particular make up more of your target audience than you think, and will do for some time. 

So, while I believe their will always be a case for building a mobile app, most marketers should look to mobile websites to add value to their customers mobile lives first. In fact, as the Web comes to TVs and other digital devices I believe the  best play is to consider your website a central store capable of adapting it's HTML, CSS and Javascript display to match the device viewing it. With the amount of device innovation we are seeing today, it's surely the only long term strategy that makes sense.

Also check out:

• Mobile Applications: Virtual Beer & Brand Awareness 
• Mobile Search Engine Marketing
• Brett St Clair of AdMob on Mobile Advertising