The D'Alembert system in online Roulette is a low-risk betting strategy where you increase your bet by one unit after a loss and decrease it by one after a win. It aims to recover losses gradually without aggressive bet increases. While it helps manage risk and maintains control, it doesn’t alter the game’s odds. Success relies on a balanced streak of wins and losses, but prolonged losing streaks can still result in significant losses, making budget discipline crucial for its effectiveness.