When you strip the noise away, the real question is simple: dark pools solve one problem — information leakage — but create another: uncertain fill quality. Mechanism: Routing orders to dark venues can reduce market impact, but you sacrifice price transparency and cannot be sure of the counterparty mix. Why it matters: That trade-off means dark routing is useful for large institutional flows but often irrelevant or harmful for retail-sized orders. Market translation: A pension fund selling $50M of a mid-cap position genuinely benefits from dark pool midpoint execution. A retail trader selling 100 shares does not. Failure mode: The mistake is assuming all dark routing is beneficial without understanding who is on the other side of the fill. Review question: Before sizing up, identify whether the edge comes from cash flow, volatility, timing or balance-sheet structure. That is usually where the edge is: not in the vocabulary, but in the structure underneath it.