A public Domain Name System server list is a list of computers that are online and currently available to translate human-language website addresses into computer-language IP addresses. Lists of public DNS servers give people a choice of computer to use as a translator, potentially speeding up their Internet service.
DNS servers direct traffic across a computer network by converting IP addresses into alphanumerical names, as when the IP address 126.96.36.199 is converted it to www.about.com. This allows users to type in website names and wind up at the correct location online. IP addresses are how computers identify themselves online, but having to recall numeric IP addresses is unwieldy, which is why the DNS was adopted by the early Web.
DNS servers take requests for translation from many different computers across a network, and they can respond slowly if they get too many requests at once. Public DNS server lists allow users to change from one DNS server to another, which can give them an advantage in response time.