And that's exactly why companies such as BT have invested in their own VoIP systems to compete with Skype (the market leader). And, as of yesterday, here comes Google.

Google Talk is at its core just another instant messaging program. It's very similar to AOL's Instant Messenger (IM) or Microsoft MSN Messenger service: you can chat to your friends using text or, if you have a VoIP handset (which start at around £10), you can actually talk as if you were making a phone call, for no cost at all. Even some plug-in ear phones from a Walkman could be enough to get you connected in full, Techicolor sound.

At first glance, there's nothing unique about Google's offering except that none of your friends or work collegues are likely to have it, since to register, you have to have an account with GMail, Google's e-mail system. In Sign-ups to GMail have been restricted so far to a "by invitation only" basis, so they are the fashionable thing to have, but they remain quite uncommon. GMail is still in beta testing, but I happen to possess an account.

And here's the rub, because the real problem with message services is that they seem to be incompatable with one another. The MSN one doesn't connect to the AOL one, and neither connect to Google's.

Google claims that this may be their unique selling point, as they are going to make their Google Talk product opensource, which means that other providers can utilise their software and network to allow their users to be able to keep in touch with more of their friends.

However, as it stands, all you'll get by downloading the application as I did yesterday is what is essentially a slimmed-down version of the exisiting IM products. Microsoft's IM has enabled users to plug in VoIP handsets and talk to their friends for years. Indeed, if you have a webcam, you can make free video calls to your mates for absolutley nothing.

Skype, the No1 VoIP product, also allows you to make outgoing calls to non-IP numbers. Thus, you can effectively telephone someone who does not even have a computer - but at a price. This paid-for service when you opt out of the computer-to-computer network allows you to call any number in the world, but still at a greatly reduced cost compared to the standard BT offering.

SipGate, a European based VoIP service, goes one better, giving you a landline number in either the UK or Germany that your non-VoIP friends and collegues can call you on. So for example, when I needed an extra phone line, rather than paying BT an installation fee and a monthly subscription, I simply opted for a SipGate number, which was free and starts with the familiar 0207 area code.

While it is clear that Google's entrance into the market will mean that many more people will give VoIP a try, it is unclear whether this product will have the Google magic that has catapulted them, in just seven years, into being the highest-valued media company in the world, generating $399 million net income last year and making the company's two founders, Larry Page and Sergey Brin, guys in their early 30s, each worth an estimated $10 billion - figures that even a former teenaged dot.com millionaire can look at with admiration.

Perhaps, Google may add the bonus of free calls to any number in the world. If they did so, then their service would be unique.

However, it is likely to come at some cost to the consumer: their privacy. I can foresee Google using voice recognition technology to analyse their users' conversations and provide sponsored links that are relevant to the words and phrases just spoken. Thus Google Talk may be just another step towards world domination by Google.

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