The text discusses the importance of experimentation and holdouts in product development, particularly within fast-moving teams like Facebook, to ensure long-term success and mitigate over-optimization for short-term gains. It highlights how holdouts, where a small percentage of users are excluded from certain features, allow teams to measure the true impact of those features by comparing metrics over time. By creating holdouts, teams can separate the effects of external factors from feature launches and evaluate both the cumulative and long-term impacts of their developments. However, the text also notes that holdouts can be costly and complex, requiring careful consideration of their size, duration, and purpose to avoid unnecessary expenses or skewed results. Additionally, the text touches on the advantages of simpler testing methods like backtests and emphasizes a thoughtful approach to experimentation, urging teams to start with straightforward holdouts before moving to more sophisticated methods.