Unlike DNS that only works with static IP addresses, DDNS is designed to also support dynamic IP addresses, such as those assigned by a DHCP server. That makes DDNS a good fit for home networks, which often receive dynamic public IP addresses from their Internet provider that occasionally change.
To use DDNS, one simply signs up with a DDNS provider and installs network software on their host to monitor its IP address. For example, dyndns.com provides a free dynamic DDNS service via software that can run on Windows, Mac or Linux computers.
Compared to ordinary DNS, the disadvantage of DDNS is that additional host software, a new potential failure point on the network, must be maintained.