If you are using a static IP then you don't mind logging in to easyDNS and updating your IP address because it will only need to be done very infrequently.

However, with dynamic IPs, you will need to change your IP much more often. Usually everytime you connect to the internet.

The ideal solution would be for your computer to know when the IP has changed and then communicate that change to easyDNS so it all happens automatically. This is what dynamic DNS service is all about.

In order to achieve an automatic IP update all you need is a domain name, easyDNS's dynamic DNS service, and a dynamic dns software client installed on your computer.