the whitepaper says that users can create their own contests and invite your friends,how much is you can invite your friends to this contest?
This function is under development and also it isn't described nowhere, so we just can't answer to you, maybe community manager will answer. Biggest contest that i saw was for 11 people. Maybe you can't do it for now because now is going contest for a 0.3 BTC and you could speculate by using multiaccount.