A Domain Name Server maintains a directory of domain names and translates them into IP addresses because computers require the IPS to access websites.
DNS servers can be DDoS'd which is a disadvantage because the user may not be able to access the website if its being DDoS'd.
The user benefits from the DNS server because they don't have to remember the IP address to access the website so instead they can remember a simple url to help them get directed to their desired website.
