By Michael Brown

Over the last year I have had several clients inquire about developing an iPhone application to complement their existing Web site or to create a separate mobile presence.

Although there are two different types of iPhone applications, without fail these clients are always referring to the kind of application you find in the iTunes App Store -- what I refer to as "native iPhone applications." These are the sexy software applications that you hear about constantly in the media and in the blogosphere.

Without question native applications are often very cool. As an iPhone owner, I understand the awesomeness of a truly good native application such as Evernote, Slacker Radio or Animoto, to name a few.

However, upon digging deeper with clients, I often discover that what they are looking to do has no inherent need to be a downloadable software application and could just as well be served by an iPhone "Web application."

What's an iPhone Web application? It is not a piece of software, but actually a Web site that is optimized for viewing on the iPhone.

These sites can offer nearly all of the functionality of your traditional Web sites because they are based on the same technology. SoapNet's application is a good example of a well-executed iPhone Web application (you can also see what the application looks like in a regular browser).

With all this in mind, I decided to break down which iPhone application is appropriate for which business need or use.

A native iPhone application is best for your business if ?

? You want to take advantage of the features built into the iPhone itself. Built-in features such as motion detection, voice detection, camera and GPS are some of the things that make the iPhone so hot and at the moment.

Right now, access to these phone features can only be accomplished using a native application. Yelp, the local business review network, would be a good Web application, but access to GPS information makes Yelp an even better native application.

? You want to make sure your content or service is available offline. If the core purpose of your application is to make your content available on-the-fly, or without a strong Internet connection, then a native application is best suited for your needs.

For example, Pocket Aid offers first-aid and CPR information that is available on your phone, regardless of whether or not you are connected to the Internet. This availability is crucial to the application's success and therefore makes perfect sense to be native.

? You are looking to make money directly from the sale of the application itself. In this case, a native application is the obvious solution.

Web applications have no proven models for paid access, and iTunes makes it way too easy for users to plunk down their money on native applications.

Of course, building a paid application doesn't guarantee a profit. In fact, most paid applications get lost in the shuffle and go relatively unnoticed.

? You are hoping to get press coverage around the launch of your application.

Although I expect this to change in the next year or so, many name-brand iPhone native application launches still garner a decent amount of press attention in the trade press. Yours just might too if it offers a nice mix of brand recognition and innovation.

An iPhone Web application is best if ?

? Your Web site has all the same content you want to feature on your iPhone application.

Since an iPhone Web application is essentially an iPhone-optimized Web site, you can use the same publishing system that you use for your main Web site. You can also use the same ad-serving software and the same Web analytics package as well.

? Your content could be deemed inappropriate by Apple. Have you downloaded the great South Park application, submitted to iTunes by the show's creators? Of course, you haven't because Apple rejected it on the grounds that it was "potentially offensive."

Submitting an application to Apple carries the inherent risk of being denied entry into the iTunes App Store. If it does get denied, you will be left with a nearly useless piece of software.

If you think that your application has any chance of getting denied by the powers that be at Apple, you might want to re-evaluate your approach and consider a Web application.

Web applications have no approval process. As long as it is not illegal, you can build a Web application that contains any content or functionality that you wish.

? You are interested in potentially reaching non-iPhone users with the same application. Apple iPhone native app development is very specific to iPhone and is not easily ported to other platforms such as Android and BlackBerry devices.

On the other hand, iPhone Web applications are displayed in Safari, which uses the open source application framework Webkit.

Since Webkit is also used as the foundation for the browsers in Android, newer BlackBerry models and the upcoming Palm Pre, a Web application built for iPhone can be ported over with little or no effort depending on the complexity of the application.

? You want your application content to appear in mobile search results. As more people take advantage of their phones' Internet capabilities, mobile search results will become increasingly important.

Users will begin to demand that the sites that show up in those results are optimized for mobile. A native application will not help with that.

A few more general considerations

? Cost. Generally, native iPhone application development is more expensive than its Web application counterpart.

This is mostly based on the fact that the skill set required to build native applications is far less common and garners a premium rate.

Furthermore, native iPhone application development is generally more time-consuming and therefore incurs more billable hours.

? Maintenance and enhancements. With either type of application, be sure to include maintenance and enhancements in your budget.

User feedback often leads to unplanned changes in the way your application looks or functions, and you don't want to be stuck with no budget to improve the experience for your users.

? Marketing. Many assume the "build it and they will come" model applies to iPhone applications. This is only the case for the biggest brands -- the rest of us have to work for it a bit.

If you are looking to drive awareness of your application, you need to support your efforts with a marketing plan.

At the very least you should consider building a search engine-optimized promotional Web site that offers deep details into the application's features and functionality.

Hopefully these tips will be helpful in deciding which iPhone application is best for your business. Whatever you do, be sure to act fast.

The iPhone and iPod touch's exploding popularity cannot be ignored and the race to engage this active and savvy user audience is well under way. Don't be left behind.

Michael K. Brown is vice president of media and entertainment as well as head of the mobile solutions practice at Digitaria, a digital marketing and technology service provider in San Diego. Reach him at .