Online dating services also differ widely in their revenue streams.
Once a profile has been created, members can view the profiles of other members of the service, using the visible profile information to decide whether or not to initiate contact.
Most services offer digital messaging, while others provide additional services such as webcasts, online chat, telephone chat (VOIP), and message boards.
It is possible that the mode of online dating resonates with some participants' conceptual orientation towards the process of finding a romantic partner.
That is, online dating sites use the conceptual framework of a "marketplace metaphor" to help people find potential matches, with layouts and functionalities that make it easy to quickly browse and select profiles in a manner similar to how one might browse an online store.
In 2008, a variation of the online dating model emerged in the form of introduction sites, where members have to search and contact other members, who introduce them to other members whom they deem compatible.
Introduction sites differ from the traditional online dating model, and attracted a large number of users and significant investor interest.
Others utilize the freemium revenue model, offering free registration and use, with optional, paid, premium services.
Still others rely solely on paid membership subscriptions.
Some have a broad membership base of diverse users looking for many different types of relationships.
Other sites target highly specific demographics based on features like shared interests, location, religion, or relationship type.
Under this metaphor, members of a given service can both "shop" for potential relationship partners and "sell" themselves in hopes of finding a successful match.