Wow. That's all I have to say after reading "this":http://www.business2.com/b2/web/articles/0,17863,1132510,00.html article. This guy has been buying up domain names for 10 years. He's making $2 *million a year* from 5,000 domains.
You can purchase a domain for $8.95 from "GoDaddy.":http://godaddy.com So from a $44750 investment (plus whatever hosting+other costs?), he's returning $2,000,000 per year. These are _huge_ numbers particularly when you consider the Australian stock market and property industry have grown on average at about 12% each year for the last 30 years.
I have been saying it for a while, domains are very similar to property. In fact I did a quick search and it turns out you can even lease domains now! _Eventually_ the domain market will turn in to the property market. Throw on your extreme hat and project from now in to the future given the current direction - all useful domains will be owned and there will be more and more people needing to use them.
All these figures are in US currency.