The MACD strategy generates buy signals when the MACD line crosses above the signal line and sell signals when it crosses below. The threshold parameter allows for a percentage-based buffer to avoid false signals in choppy markets. The strategy keeps track of the last signal to avoid generating multiple buy or sell signals in a row without an intervening signal of the opposite type. The threshold is applied as a percentage difference between the MACD line and the signal line to determine when a crossover is significant enough to generate a signal, helping to filter out noise in volatile markets.