In soccer, advantage usually refers to which team got 'advantage' after a foul was called. For example, if team A has the ball and is driving towards Team B's goal when a player from B fouls the ball carrier from A, the referee may not immediately blow the whistle. Instead they will judge if Player A was negatively affected by the foul, giving Team B the 'advantage'. If not, they may let play continue to Team A can continue to attack the goal and score. Otherwise a defending team could break up attacks on goal by committing cheap little fouls that would stop play. Good referees will work to allow the game to flow with minimal stoppages - so they only want to call fouls that gave the fouling team an advantage.
Coaches, this is just a friendly reminder. Don't get too upset if I don't blow my whistle immediately when a foul occurs. There is a specific reason why I do so. I want to give the attacking team a chance to apply the advantage to their benefit, rather than stop play and become the defending team's "12th defender." I have seen many goals scored because I allowed play to continue because the attacking team had an advantage. However, if there is no foreseen advantage I will immediately blow my whistle. The spirit of the LOTG promotes continuous play. We are not basketball refs here.