You can use equipment and services you already have

Why would you want to use the Internet to manage phone conversations? First, you already have it (and pay for it). Internet use is widespread; it seems that nearly everyone has it. The technology keeps improving every day. If you already have access to the Internet, you can handle much of your long distance calling over the Internet for very low cost or for free, and often with better sound quality than you get from cell phones and regular phones. Also, you may be able to do things with an Internet-based phone system that you can’t do with a conventional phone system. You can run a Skypecast with a hundred people. You can send and receive files that would choke your email system. You can send and receive live video from anywhere in the world. Better yet, all these transmissions over Skype occur on secure and encrypted lines of communication.