Intermediary services under GST hinge on facilitation of a main supply, with place of supply generally linked to the supplier. Place of supply for intermediary services is generally the location of the supplier where either the supplier or recipient is outside India. Intermediary means a broker, agent, or similar person who arranges or facilitates a supply between two or more persons, but does not supply the main service on his own account. The concept requires at least three parties, two distinct supplies, and excludes principal-to-principal supplies and subcontracting. Circulars also clarify that certain advertising and data hosting arrangements are not intermediary services, while a limited exemption applies where both supplier and recipient of goods are outside the taxable territory.