Clubs are private groups with their own markets, for when the argument is with a specific set of people rather than everyone on the board.
A group with its own set of markets. Anyone can start one and invite people, and the markets inside it work exactly like the public ones — a Yes/No question, a deadline, and resolution against public evidence. The difference is who is arguing.
No. Clubs use the same play credits as the rest of Stips. There are no deposits, no withdrawals, and credits cannot be converted into currency. A club is a way to keep score among a group of people, not a betting pool.