Just when you thought the internet couldn't be any more useful, along comes VoIP.
It stands for Voice over Internet Protocol, and involves making telephone calls over the internet instead of via the traditional telephone system, known as the Public Switched Telephone Network (PSTN). It is a revolutionary technology that has the potential to completely rework the world's phone systems.
So how does it work?
The VoIP system uses the internet as a method of transmission rather than a landline. The VoIP user can use a phone or headset to call either another VoIP user or a PSTN user via a broadband connection on their computer.
You need three things to use VoIP.
The first is a VoIP-enabled telephone. This could be a normal telephone with an adaptor that plugs into the broadband connection, a headset and microphone that uses software on a computer, or an actual VoIP telephone.
A broadband internet connection is mandatory. Anything less will mean a reduction in sound quality.
And finally, you will need to set up an account with a VoIP service provider who will give you a VoIP external number which other people will dial to get in touch with you.
The main advantage of using VoIP is the low cost. All calls to other VoIP users are free and any landline calls are usually competitively priced, if not lower than landline service providers' calls.
Costs vary between VoIP service providers and there will generally be a one-off set up charge and a monthly rental charge for the number. However, it is advisable to check if it actually works out cheaper as it may not always be the case. Some VoIP providers offer packages where they combine monthly rental charges and unlimited calls.
VoIP also offers more sophisticated features such as call waiting and caller ID. If a business has workers across the country or they each work from home then VoIP creates the opportunity to give them all extensions on the same telephone number. This gives customers the impression that you all work from the same city centre head office.
There are some downsides to the service.
For a start, it is very much a work in progress: it will still be at least a decade before communications companies can make the full switch over to VoIP. As with all emerging technologies, certain hurdles have to be overcome.
The PSTN is pretty robust and rarely fails as a system for delivering phone calls. On the other hand, computers and email are prone to hiccups and most of us expect our network to go down from time to time. The internet is far more complex and therefore has a greater margin of error. Reliability is perhaps the greatest flaw in the VoIP system.
Also, with VoIP, no power means no phone. So in a power cut you would have no communication. Another consideration is that there is currently no way of integrating digital video recorders, digital TV services and home security systems with VoIP.
Colin Bryant, director of telecomsadvice.org.uk, says that for a fledgling business, it is wise to consider the risks of using VoIP.
"The quality over the internet can be poor and increasing uptake and increasing congestion will only make it worse," he says.
"We are relying on the major telecoms companies to upgrade their internet infrastructure to keep up with demand - but they are likely to be the losers if VoIP over the internet eats into their core business."
If you choose to go ahead with the service there are a few questions you should ask of your provider before you subscribe. You should ask whether they offer access to emergency services' numbers and, if you do call 999, will they automatically know where you are.
If there is a problem with your broadband connection, will the provider let you make back-up calls via the PTSN connection? Does the service depend on your power supply and if so will the provider supply back-up power when there is a power cut?
Finally, enquire about your telephone number: will you be able to keep your number if you decide to transfer to another provider in the future?
If you choose to opt for VoIP then you'll be joining a growing band of devotees. According to Ofcom, there are an estimated 500,000 active users of VoIP in the UK, a number forecast to grow further over the next few years. Industry analysts have predicted that by the end of 2007, there will be about three million computer-to-computer VoIP users.