Such sites earn revenue from a mix of advertising and sale of additional options.
This model also allows users to switch between free and paying status at will, with sites accepting a variety of online currencies and payment options.
Some sites are completely free and depend on advertising for revenue.
Others utilize the freemium revenue model, offering free registration and use, with optional, paid, premium services.
Introduction sites differ from the traditional online dating model, and attracted a large number of users and significant investor interest.