Three originally distinct concepts - lipid rafts, detergent-resistant membranes (DRMs) and liquid-ordered (lo) lipid phases - are often confused in current literature; many researchers have assumed that all three names refer to the same chemico-biological entity. In fact, theoretical and experimental findings provide strong evidence against identifying DRMs with rafts and lo domains. Because much of what we think we know about lipid rafts is based on their unjustified identification as DRMs, functional domains in biological membranes might differ markedly from the generally accepted picture.