Each token entitles its owner 1/22-millionth of all market trading fees in return for faithful reporting on market outcomes.
I did some calculations on how much you can earn with your REP tokens in return for reporting on market outcomes.
Let's say $10,000,000 is being traded on market predictions a day when the Augur network is live (the same as the current Ethereum daily volume). Let's say the avarage fee is 1%. That makes $100,000 in fees a day. If I have 100 REP I own 1/220,000 of the total available supply. I would make $100,000 / 220,000 = $0.45 a day. It would possible be higher if not all REP is being used for reporting.
So 1 REP would make $0.0045 a day. Not much. In that case the current value of 1 REP at about $9.80 is in my opinion way too high.
Am I right on my calculation?