What is domain propagation?

When a domain name is registered, the details for the domain name are sent to the relevant domain registrar. From this information the DNS on other servers gets updated.

Because they are not all updated at the same time, it can take 24 - 72 hours for all the servers to show the updated information. During this time the information that is shown depends on the DNS that is queried and whether or not it has been updated.

This also occurs when any changes are made to a domain name. The old information could be shown intermittently. The time it takes for all DNS to be updated is known as domain propagation.

For more information: InterNIC FAQs on the Domain Names, Registrars, and Registration