Are you looking for an idea for an online startup, wish you had of thought about, Youtube, Myspace, Skype, eBay, Amazon etc. Well here is a list of some of the Top Australian start-ups.
Once an idea is already taken on the internet it is hard to compete, so you probably don't want to go head to head with any of these unless you.
1. Can come up with a fundamentally better ways to do things. Note: the customer / user must also see it as a fundamentally better way to do things.
2. You have a fundamentally better business process that makes you competive.
You can however, get inspiration from some of these businesses, and use a bit of creativity to come up with a new idea. More often than not innovation is not the creation of a totally new idea, but the pulling together of several old ideas in a different way.