If you make your living on a contractor basis via the internet, there’s a good chance you use oDesk (which has the highest annual freelancer earnings) and/or Elance (the oldest/most popular freelance site). If you’re just starting out, these are both among the premier media for connecting freelancers with people looking to exploit freelancers.
Just kidding. Most people don’t do that.
I still remember when I was starting out as a fledgling freelancer. It feels so long ago (actually just over a year) that I asked Google, “Which one is better, oDesk or Elance?” These are the answers I wish I could have found back then.