I've been playing with it and have already earned a few miles clicking around. Their little calculator function says that if you refer 5 people and click on 4 ads per day then you will earn over 2 free RT tix per year. I'm dubious of this, or figure that at least it's based on those 5 people each signing 5 who sign 5 etc. Haven't done the math. But here's my link, and I'd love to be your referral:
http://www.milesource.com/join.php3?referrer=steffo