The business brainstorming session has come up with its latest, greatest idea: an iPhone app that lets customers interact with the business.

On the face of it, the idea sounds OK. All the coolest dudes are using iPhones to communicate with their friends and colleagues; all the coolest companies are creating apps that give their clients a new way to work with the business.

Rolling out the application should mean one million-plus UK iPhone users will be able to log in and communicate with the business. But there’s a world of difference between creating a cool app and creating a useful app.

Let’s take the area of online banking as a case study example. Research suggests one third of small businesses would consider using mobile banking if their financial institution offered such a platform.

The result is that companies are queuing up to offer online banking solutions. Financial institutions are looking at ways to offer their customers authentication on the move, and suppliers are looking to create a new wave of secure applications.

But is that really the best way to turn ideas into realities? Shouldn’t we be starting with the business case and then thinking about potential technical solutions?

After all, one million-plus iPhone users does not necessarily correspond to more than a million happy customers. Not all iPhone users will hold an account with the bank, and not all banking customers will want to use an iPhone application to undertake their financial activity.

Even in a best-case scenario – like that above, where a third of small businesses will like to undertake mobile banking – the results are likely to be less than staggering. Rather than a million potential users, what the business is left with is a proportion – a small sub-set of its existing customer base.

Which is great if you find the right niche. It’s also great if your main aim is to look interactive – the iPhone app is up-and-ready and the customers are being served through the latest, greatest platform.

But developing and then maintaining a new channel to market is expensive. At a time of reduced IT investment and increased demands for value, the last thing you – and your business leaders – need is more costly software and systems.

The real pay back from mobile technology comes from mass adoption. Undertake research and development, and ensure your app provides a real return on investment. Otherwise, you’re simply trying to look cool and trendy. And that’s a business case that is unlikely told hold credence in the boardroom battle.