By 2016, one quarter of the world's population will be using a smartphone, according to some estimates.
But with the bulk of the population in western countries already owning Android and iPhone devices, how might future handsets stand out from the crowd?
Modern smartphones are computers first and phones second.
But having a world of internet-connected mobile apps in the palm of your hand adds weight and cost and diminishes battery life.
What if you want a phone and nothing more? The makers of a new Kickstarter project are hoping to meet the demand for such simplicity.
Light Phone is a credit-card sized handset that will let you make calls and not much else. There are no apps or web browser and the display is a simple LED Dot Matrix strip similar to what you'd find on a calculator.
This no-frills approach lends the phone advantages over smartphones, with its makers claiming the battery will last for 20 days. The GSM phone supports 10 speed dials and charges via Micro USB.
Mirroring the phone's stripped-back functionality is the handset's minimalist design, with the prototype coming in a simple white case with an illuminated keypad occupying nearly all of the device face. At just 4mm thick and 85.6mm by 53.98mm in size, it can be slipped into your wallet. The case also lights up, allowing the handset to be used as a flashlight.
Backing the project for $100 will get you a handset, 500 minutes of pre-paid calls, a charger, microSIM card and an iOS or Android app for managing the phone.
As with any Kickstarter it's worth bearing in mind you have no guarantee of getting a finished product. The first phones are not scheduled to ship to backers until May 2016.
We may never need to plug our mobiles in again, if bets by technology giants such as Samsung, Qualcomm and Intel pay off.
The big three are all backing the Rezence standard, which would allow devices to suck up power from wireless chargers. Mobiles that can charge wirelessly via Rezence will be released this year, according to Intel.
Rezence chargers are able to beam power to multiple nearby devices through furniture and clothing, up to a distance of about 5cm. The vision is that homes and cafes could have chargers situated near to places where phones and computers are used, such as the underside of tables, so they could unobtrusively transmit power.
Various electronics have supported wireless charging based on electromagnetic induction for a number of years, yet it never really took off. But Rezence charging relies on a slightly approach known as magnetic resonance and has been developed by the Alliance for Wireless Power, which has the backing of major companies, so may fare better.
Blending the real and digital world
Similar world-twisting technology is headed to phones. Google's Project Tango is a prototype phone that can build 3D maps of the real world as you walk through it.
Supplying computer systems with these maps makes a variety of new applications possible. Home owners could see which virtual sofa looked best in their living room before buying. Gamers could generate 3D worlds based on their own neighbourhood.
As a company that relies on harvesting data to target ads, Google likely also has a vested interest in persuading people to map their homes and the wider world for them.
Tango uses a motion tracking camera, four megapixel camera, and a depth sensor to make more than 250,000 measurements every second, updating the position and rotation of the phone and fusing it into a single 3D model of the environment.
Phones are also beginning to be used to realise virtual reality, with the Samsung Gear VR, a headset that enables the user to snap in a Samsung Galaxy Note 4 phone to create a VR head-mounted display.
At about $200 for the headset and close to $1,000 for the phone the Samsung Gear VR is not the cheapest option. Those who want a taste of VR on the cheap can try Google Cardboard, which allows you to build a wearable rig by slipping an Android phone running Jelly Bean 4.1 or newer into a cardboard headset costing as little as $2.
Upgradable and customisable
The joy of breathing new life into a creaky old PC by swapping out its parts is difficult to realise in an age of tightly-sealed gadgets.
Google is hoping to make phones more tinkerer-friendly with Project Ara, a concept for an Android phone made up of upgradeable modules.
Each module slots into a frame, with separate modules for the central system-on-a-chip, memory, wifi, display and battery.
Beyond making it easier to rejuvenate old handsets, the approach would allow users to to build a phone that suits them - to prioritise a better battery or sharper screen at the expense of another component.
Ara-style phones will be held together by electromagnets, which can be disengaged to take it apart, and modules swap data via 10 or 20Gbps network connections.
A Project Ara device will go on sale as part of a pilot in Puerto Rico later this year, and it's yet to be proved whether there is an appetite for customising phones in this way among mainstream consumers.
A perennial prediction in the tech industry is that phones will soon have screens as flexible as paper.
But while the pliable phone may have been forecast for as long as the smart fridge, handset makers haven't given up on screens that bend, fold and roll.
Curved screens have already arrived, in products like the Samsung Galaxy Round and LG G Flex, and Samsung has announced it hopes to launch a phone with a screen that can be folded in half this year. The handset maker has been working on such displays for a number of years, unveiling a prototype screen that could be rolled up like a scroll at the Consumer Electronics Show back in 2013.
If an actual product does make it on sale in 2015, it could help bring bigger screens to mobile devices without compromising their portability.
Unfortunately technical challenges may continue to delay the release of any such screens, with a Samsung exec recently hinting its foldable screen may now be released in 2016.
Nick Heath is chief reporter for TechRepublic. He writes about the technology that IT decision makers need to know about, and the latest happenings in the European tech scene.