A domain name allows your own unique identity.
This applies to your website and your email address.

If you wish to change your Internet Service Provider, your domain name does not change.
This allows you to print stationary with your permanent domain address - both website and contact email - these will not change as long as you renew your domain registration.

Having your own domain name allows people to remember your address.

Some search directories such as Yahoo only index websites with their own domain name.

Choosing a domain

Short domain names
Short domain names are harder to find. It is easier to brand, easier to remember and it's harder to misspell.

Easy to remember
Try and register a domain that easy to remember and sounds good. If all the required names have been registered, seek alternative word arrangements, combinations that sound good together. The domain "williamtell.com" is an easy to remember name.

Relevancy
It is better to have your actual business name or a name similar to your company name as your domain name, this way all your product branding will pay off online as Internet clients should be able to guess your domain name from your business name.

Avoid similarities
Avoid choosing domain names that close to existing domain names - your clients could get confused and end up on another similar sounding website.

.com or .com.au for commerce
If you have a business, try and obtain a .com or a .com.au domain.
Australia .com.au registration is strict and you will have to provide proof of a registered business.
The advantage with this Australian registration is that it verifies that there is an actual business connected to the website. Alternatively, a .com domain could mean anything.