Why Register Multiple Domain Names?
So why would you want to register more than one domain name?
The answer is quite simple. There are a number of advantages to registering multiple domains.
If you register your business name (eg sydneyelectrics.com.au) you can also register other names that people may search for you under.
In the above example you may sell light bulbs, so you might register lightbulbs.com.au as well.
Having more than one domain name does help you in getting better positioning in Search Engines, like Google, expecially if they are descriptive.
Protect your brand on the Internet:
If you register sydneyelectrics.com.au you should also register sydneyelectrics.com.
The subtle difference is not always obvious, but you don't want to have your competitor getting traffic that should be destined for your web site!