There are several advantages to using Voice Over IP, including advanced features that standard telephone systems are not capable of and the ability to have a phone number usually associated with a particular local area anywhere in the world. But the biggest single advantage VoIP has over standard telephone systems is cost. VoIP providers in the United States now offer unlimited calling throughout the country (and even Canda) at a fraction of the cost of a standard telephone line. In addition, international calls using VoIP are usually very inexpensive. One other advantage, which will become much more pronouced as VoIP use climbs, calls between VoIP users are usually free. Using services such as Free World Dialup, subscribers can call one another at no cost to either party.