If you go to their web site, they spell it out quite nicely in their annual report:
http://content.idine.com/pr/rn/inves...ual_Report.pdf

I believe, back in the old days, when they offered 10 mi/$ or 20% back across the board (with some restos at 20 mi/$ or 40% back), for the base rate, they received 40% of the revenue. If restos wanted to add any more, they just paid that straight to the consumer. So for 40% back, iDine would take 60% and pass on 40%.

Now there are two types of resto programs: marketing credit and marketing service. With the marketing credit program, RN actually gives the restaurant cash up front, essentially purchasing meals at at discount. RN then gets a credit with the resto. Then when a customer goes to the resto, RN takes X% of the revenue and offsets the credit they already built up. For 2004, X% seems to be close to 75%. Now of that amount, it appears that RN has already paid out about 50% of that in marketing credits. So here's how the breakdown would work. RN gives Restaurant A $1500 and gets $3000 in marketing credits in return. For the next $4000 the restaurant does in RN customers, RN gets 75% (or $3000). So essentially RN gets about 37.5% of the revenues. Obviously

For the marketing service program, RN pays nothing upfront and just gets Y% of revenue the resto gets from RN customers. For 2004, this appears to be about 24%.