I live in Darwin and order online all the time. With online shops, I check them out a bit, more to see what they've got than to sus out whether they're dodgy or not. You usually figure out what they're about by doing this.
Usually I order from well known places, but the odd times I've bought from smaller, less well set up sites, it's always worked out fine and I've gotten good deals. One time, I ordered some tyres from an random site and they arrived super quickly which was great. Then they contacted me a week or so later saying that they were still waiting for me to pay! I checked my banking details and sure enough, the transfer hadn't gone through so I zapped it to them ASAP. That's trusting eh...
I try and buy from forums whenever I can because you can get good deals off people who are into the gear. There's always an element of risk and there's always a point when the seller either has to send the product before they've received the payment, or more frequently, I have to pay and hope that the item is sent. Once again, I've never been burned doing this.
It's all about trust. Most people are genuine.