The company claims that this is to protect users from viruses and the like, and to make sure that the iPhone continues to run smoothly without some poorly written application crashing the handset or eating up the memory.
Apple has stated that it will open up the platform to third-party developers in the future, presumably with suitable protections in place to ensure stability and security.
For the time being, though, users are stuck with what comes pre-loaded on the phone, so I'll go into these and see how well they work.
Because all the applications have been developed from the ground up for the iPhone, they all have a very similar look and feel, which makes navigating the individual programs easier. But there are some inconsistencies that I found frustrating.
First and foremost is that very few of the applications make use of the tilt sensor. While it doesn't necessarily make sense for the Clock program to have a landscape mode, apps like Text, Email and Notes could really benefit.
This is primarily because the keyboard is a hell of a lot easier to use on its side; the keys are better laid out and it's much easier to hold the phone and type with both thumbs.
Another limiting aspect to the applications is the inability to copy and paste text. If you have an address in an email, for instance, you can't copy and paste it into Google Maps to look up the location. You have to memorise or write down the details.
The Text application has a nice 'threaded SMS' feature which displays all text communication between two people in a list, providing a more 'instant messaging' feel to the conversation.
While this feature is quite nice, it means you can't forward texts or send to multiple recipients.
The Calendar, Calculator, Notes and Photos applications work pretty much as you expect and the use of the tilt sensor when viewing photos is a nice feature.
It has to be said that the camera is pretty unimpressive. In good light levels with little movement the picture quality is decent for a 2-megapixel camera, but the lack of flash, zoom and video are pretty serious omissions.
Apple has also included a strange collection of bespoke applications, namely YouTube, Stocks, Maps and Weather.
Each application does pretty much what it says on the box, and the Maps feature is particularly useful, although it could do with a pedestrian mode when it comes to giving directions.
What strikes me when looking at this collection is the lack of focus. The YouTube application is clearly aimed at the younger consumer demographic, but the Stocks application is obviously for a business user.
This is indicative of something I'm starting to feel with the iPhone: in many ways it is a great device, but it seems to lack a focus.
It's obviously aimed primarily at the 'prosumer', cutting edge, fashion conscious, high earners with a fair amount of disposable income.
But it seems to flip-flop between being a business phone, with a big push on email and internet access, and a consumer device, with the focus on YouTube, threaded SMS and similar features.
I think I understand why. The iPhone is not cheap; the combination of an 18-month contract of £35 or £55 a month on top the £270 outlay means that customers who are not rabid Apple fans are going to think twice before buying one.
This means that many potential owners are going to need a way of justifying the expense to themselves, and positioning it as a smartphone is a great way of doing that.
Except that it can't really be called a smartphone until Apple includes a much richer set of office-level functionality.
Tomorrow, I'll take an in-depth look at two of the iPhone's most featured applications: Safari, touted as the 'full internet on your mobile'; and the iPod, which Apple reckons is the best it's ever made.
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