VoIP firm Jaxtr has announced that its userbase has grown 10-fold to five million members in the 140 days since July.

Jaxtr claims it is the "fastest growing internet communications service in history ahead of Skype, Hotmail, and ICQ", posing the question: which web giant will get its wallet out first to snap up the Jaxtr phone/web link-up offering?

As a Jaxtr member, you can make and receive phone calls in 220 countries using your regular landline or mobile number, thus bypassing international calling charges. Mobile VoIP calls don't even require a computer or an internet connection, says the company.

Follow the link

But how does it actually work? When you sign up for the Jaxtr service, you receive a link that allows your friends and family to call you using their regular landline or mobile phone. When someone wants to call you, they click on the link, enter their number and when you pick up your phone, their phone rings to let them know that the call has been connected.

Callers can save the local number provided by Jaxtr and use it whenever they want to call people overseas without being tied to their computer. There's nothing to download, and you don't even need an internet- or Wi-Fi-enabled phone. If you have voice minutes included with your subscription, you can use these to make international calls from your mobile phone.

You can also link up all your phone numbers (home, work, mobile) if you want, and then choose which one to pick up when you receive a call.

Use your existing phone and number

Rebecca Swensen, a research analyst of VoIP services for IDC, says Jaxtr is one of a new breed of VoIP providers. "The new wave of VoIP services allow users to enjoy the benefits and simplicity of placing phone calls through their existing phones by selecting a name from the contact list and hitting the green 'send' button."

The rapid growth of Jaxtr surely means that it's only a matter of time before it gets snapped up by one of the web giants. We've seen it before: YouTube being snapped up by Google; MySpace being bought by NewsCorp; and VoIP firm Skype being touted by eBay. Jaxtr is not yet in the same league of size as many of these purchases, but it has one thing in common - questions over how it will make money.

Jaxtr doesn't rely on advertising so it will have to make revenue somewhere. But, give Jaxtr its due; the service only launched in March this year. We predict it will have a line of suitors before its first birthday.