There are several types of agency appointments for real estate agents: - Exclusive agency appointments obligate principals to pay the appointed agent a fee even if the agent was not effective in closing the transaction. - Sole agency appointments only require payment of fees to the agent if they were effective in closing the deal. - Sole joint agencies involve the agent and principal working as a team, with fees divided according to a pre-agreed formula. - Joint agencies only pay the agent who closes the deal. - Ad hoc or open listings engage agents on an as-needed basis, with fees only paid upon successful conclusion of deals.