By Jo Twist
BBC News science and technology reporter
Mobiles are getting increasingly powerful in terms of processing power, and graphics technology.
The mobile industry keeps packing in more functions
They are also turning into storage devices in their own right.
But the mobile phone industry is in danger of confusing people in its quest to pack everything into handsets, thinks Scott Jenson, a leading mobile industry design consultant.
"The mobile phone industry is getting very repetitive," he told the BBC News website.
"Initially it was, the web is hot, the phone is hot, so web plus phone must be hotter.
"So first we had the WAP fiasco. We had phones are hot, cameras are hot, phones plus cameras are hotter, and that went nowhere.
"And guess what? We're doing it all over again with iTunes.
The mobile industry is full of excitement about music. Nokia, SonyEricsson and Samsung are all making an assault on music with their latest models.
But converging all these functions that are now possible into one device opens up major design problems.
What the industry should be coming up with are more innovative ways to get at these functions, thinks Mr Jenson, in ways that understand the kinds of experiences people want. It is about simplicity through design.
Mr Jenson was talking at a Microsoft Research conference about simplifying computing, held in Cambridge, UK, where he tackled the problem of the awkward term, "user interfaces".
Simply put, that is the way a device presents its wares and functions, and how to get to them, to people.
The problem facing the technology industry is how to design devices that do what they are supposed to do, easily.
Mr Jenson works with the biggest names in the mobile industry to come up with ways of doing this.
A former director of Symbian's Design Lab, published author, leader of numerous mobile design projects, and early interface pioneer, he should know a good interface when he sees one.
He also was part of the original Apple Newton team. The Newton was one of the world's first personal digital assistants (PDA) first released in 1993.
To him, design is not just about looks. It is about removing obstacles of use for everyone.
Changing the experience
The iPod, the top-selling digital music player, is a prime and oft-used example of what Mr Jenson calls a "transformative technology".
Its design success is partly down to its minimalist outer shell and peripherals which appeal to a diversity of tastes.
But its main design triumph has been to think about new features which have actually changed the way people experience their music, argues Mr Jenson.
"Apple actually said if you are going to have a hard disk and thousands of tracks, aren't you going to need to scroll through these things," explains Mr Jenson.
The iPod knocked down barriers to getting at functions
A new bit of what Mr Jenson calls "hardware kitsch" was invented by making the scroll wheel the central design feature, but that is not all.
"From a software point of view they were very clever about acceleration. If you scrolled a little bit, it was obvious. Then when you scrolled faster, it got to the bottom.
"So you could go from top to bottom of 3,000 songs in 10 seconds. And no one really even noticed that - it was invisible design"
Essentially, it did so many things without the user having to think too much about it and knocked down barriers to getting at functions.
"The device basically became effortless. That didn't mean it had value, it just means it didn't suck."
The mobile industry has watched iPod's success carefully in its quest to find the "next big thing", says Mr Jenson.
It knows it has to make use of ever-increasing processing power and other innovations, such as high-speed net access, to make money.
No longer are simple voice calls - the mobile's original function - the main cash generator.
But cramming multiple functions into a mobile is still problematic. Mr Jenson is currently working on a product with a company that is a "mobile phone-iTunes type thing", he says.
Their focus group with children told them that they listen to their iPods until every last drip of battery power has been eked out.
There are some promising ways to access functions on the way
But if they do the same with a phone they can no longer use it for its primary function, making a call.
This does not mean there will not be iPod-type phones, it is just that other unintended consequences, such as power issues, have to be dealt with by consumers.
Then there are the ergonomic issues - fitting functions with the number of buttons there are available.
"You don't want to carry eight batteries and eight screens. At the same time you don't want a device that is just horrible at everything. And how do you balance that? I am not sure what the answer is."
What he does know is that the solution the industry can learn from previous design successes as well as mistakes.
For example, having a dedicated camera function button on the side of the phone seems to work for many.
But he thinks a limit is being reached with what can really be done with buttons.
Future developments, like multifunctional rubber conductive keys, hold some promise for the future.
Mr Jenson is personally excited about cheap, widely-available electronic paper.
"I think we will get blind-sided by technology that is going to be used in a totally different way. When you get three rollable [e-paper] screens, what does that mean?"