VOIP (Voice over Internet Protocol) is a technology that allows users to make phone calls over the internet instead of traditional phone lines. It works by converting analog voice signals into digital data packets that can be transmitted over the internet in real-time. VOIP can be used by anyone for free using applications like Skype, and is popular for both private use due to its low cost as well as corporate use in products like Xbox Live and FaceTime. Common applications that use VOIP technology include Skype, gaming platforms, and video conferencing software.