The gambling site owner have to earn money through the house edge, so you can't expect there is no hous edge.
That is exactly what we offer. We offer 0% fees on all sport bets:
https://www.fairlay.com/event/category/soccer/ Since we don't take a position but instead user bet against user the average user has an expected value of 0. If your bets are better than the average user your bets will make money in the long run.
Fees and house edge are quite different things all together.
On sport betting sited the "house edge" is usually the spread of the odds. However - we are an exchange where user bet directly against each other - so there is no spread. A dice site could operate with 0 house edge as well if bets where user against user.
PD has or used to have PvP dice. not sure what state it's in now. didnt seem very fun. i would assume that sooner or later, the house would invoke a "rake" on it to monetize it somehow. Unless it was a real source of traffic for the site (then you just cover the cost as marketing)
so i assume you guys aren't making any money off the PvP bets? where does your rake come into play then?
You are right - it is similar to a marketing expense too us. We have 0% fees on the p2p sport bets - especially because here everything is done automatically - the obviously have data feeds for the sport events. On all other events like: will the block size limit be raised by march 2016 we need to moderate them and so we take a 2% fee.