[taffronaut]

I respectfully disagree. Brokers are a subset of middlemen. In many industries the role of a broker is well-defined and often regulated. A middleman can be a broker, an agent, a facilitator, price comparison site, wholesaler or any other intermediary mechanism. For organisations which seek to own all aspects of the intermediary space, and with a generally opaque representation of benefit to both suppliers and clients, the use of the term middleman seems more appropriate.