A wide variety of business-to-consumer relations are intermediated online by providers operating multi-sided services that are essentially based on the same ecosystem-building business model. In order to capture the relevant services, online intermediation services should be defined in a precise and technologically-neutral manner. In particular, the services should consist of information society services, which are characterised by the fact that they aim to facilitate the initiating of direct transactions between business users and consumers, irrespective of whether the transactions are ultimately concluded online, on the online portal of the provider of online intermediation services in question or that of the business user, offline or in fact not at all, meaning that there should be no requirement for any contractual relationship between the business users and consumers as a precondition for online intermediation services falling within the scope of this Regulation. The mere inclusion of a service of a marginal character only should not be seen as making the aim of a website or service the facilitation of transactions within the meaning of online intermediation services. In addition, the services should be provided on the basis of contractual relationships between the providers and business users which offer goods or services to consumers. Such a contractual relationship should be deemed to exist where both parties concerned express their intention to be bound in an unequivocal manner on a durable medium, without an express written agreement necessarily being required.