Does Augur's REP exist as Ethereum coin contract?
If so, does the coin contract already deployed on the Ethereum blockchain? What is the contract address for it?
If not, how do you know how many REP is owned by crowd-sale buyers?
You can "keep rep" by storing it in any ethereum wallet you have access to the private keys of.
Private keys can own/control contract data on ethereum
Rep will exist as a token contract; not deployed yet