Few can have failed to notice the business and consumer appetite for mobile devices; first laptops, PDAs and mobile phones, then netbooks, smartphones and now tablets – lots of them. Mobile networks have proliferated further boosting the appeal; cellular with relatively ubiquitous mobile data at reasonable cost and cheap, higher speed Wi-Fi at home, the office and increasingly in public places.

But as it is difficult to use more than one device at a time, where are all these mobile devices going to be used? They are all portable, but each carries a weight, space and power commitment. There is also a cost and a need for network contracts and ultimately a limit on the number of devices that any one person needs.

There are some who, especially in affluent markets, or technology-oriented job roles (anyone in tech, comms or media industries) will want to carry a multiplicity of laptops, tablets, smartphone and perhaps also have an enterprise provided ‘dumb’ phone and a desktop computer, but is that a reality for every employee? No. Not only could the business not afford to buy them all, it couldn’t afford to run them all either.

For many with allocated desks at work, the laptop is already cannibalising the need and budget for a desktop computer. The desktop replacement laptop might still be a large and cumbersome beast for many, but it is portable, allowing employees to use it at home or while travelling, and it gives the business an opportunity to consider hot-desking, workplace flexibility and other premise space reduction strategies.

Similarly the need for a fixed phone for all is being undermined on two fronts; soft phones running voice over IP (VoIP) on a variety of computers and the ubiquitous mobile phone. But, while VoIP telephony is still typically integrated into the corporate PBX, according to research most business are only just starting to get mobile phones to work like extensions on the corporate phone network, so more work is necessary for mobiles to completely replace fixed handsets.

For each element the organisation is looking to consolidate to reduce costs and make processes streamlined and simpler for the employee to get them to be more productive, while building flexibility to fit with changing working practices. At the same time, employees as consumers have become much more aware of what technology is available, and what they prefer to use, so enterprises are having to deal with an influx of consumer devices into their IT and communications systems.

Every device that is introduced carries a cost and brings complexity, and while businesses will increasingly allow employees to self-chose (BYOD – bring your own device), neither party is likely to want employees to have one of everything – smartphone, simple mobile, laptop, netbook, tablet. So as new devices appear, many will eventually substitute older ones as the constraints of earlier generations of technology are lifted and working styles change to take advantage of new opportunities.

So with tablets like Apple’s iPad appearing to be suddenly taking both business and consumer worlds by storm, and ultimately a limit on budgets, desks or shoulders to carry portables – what exactly are they going to replace?

Some may see the current crop of tablets as having the same limited degree of success that the first generation of devices called tablet PCs (in reality they were typically laptops without keyboards) enjoyed, but something has changed.

Sure the technology is better; communications networks have improved, the devices are lighter, have far longer batter life and brighter screens. However, the main changes are in the way the devices are used.

The user experience has improved dramatically, with sensors for orientation and movement, and touch screens that are suitable for simple typing as well as complex on screen interaction and gestures. Through the success of the app store model, thousands of flowers have bloomed with a rich ecosystem of applications, allowing users to simply pick a portfolio of options that meet their needs.

Despite being personal and absorbing to the individual, today’s tablets are also easy to share, to show something to a colleague or customer without the technology appearing to dominate or intimidate. It might not be the best form factor for content creation, where power, keyboards and other input devices are required, but it is ideal for consumption and collaboration. This fits the business IT needs of many roles in many organisations for much of their working time – as well as meeting many leisure needs.

So are the current generation of tablets a threat to the laptop and desktop PC?

There are parallels with the workstation versus PC argument of the late 80s and early 90s – only a small percentage of the workforce ever really needed the power of the workstation, most simply needed the access to information and a bit of manipulation delivered by a PC. Now as employees are liberated from their desks, do many really need to take anything more than a tablet for access to IT services? Probably not, so laptop and desktop deployments will be affected.

Enterprises might ask the next question – do employees need a smartphone in addition to the tablet, or will a smaller pocket-able communicator suffice? It could be that Star Trek had it right all along – communicator for voice plus tricorder for data – but I believe that most individuals who have become used to their power will probably ‘cling on’ to their smartphones.

However, tablets and their cannibalisation effect on both desktops and laptops, are another matter. They are fundamentally changing our relationship with technology, and their impact will persist long after the hype from the current frenzy of product releases has died down.