I'd like to start trading on the Augur. Which cryptocurrency can be used for transactions, Bitcoin or any other internal currency?
Initially, only ETH or shares in other Augur markets will be allowed. There are plans to switch over to a stable coin, once one has proven itself (e.g., DAI). Long term the plan is to allow markets to be denominated in any token, though that is still up for debate as it could lead to fragmentation and there are some hard engineering problems that need to be solved first.