An open position is created whenever a player has an unbalanced number of buy wagers vs. sell wagers in a given market. If a player has bought more contracts than they have sold, they want the price to go up and the market to result as YES to be profitable. If a player has sold more contracts than they have bought, they want the price to go down and the market to result as NO to be profitable. The Position count aggregates all the contracts bought/sold in a given market so the player doesn't need to track hundreds of bet slips, we do the math for you!