Profiles created by real humans also have the potential to be problematic.
For example, online dating sites may expose more female members in particular to stalking, fraud, and sexual violence by online predators.
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.
Niche sites cater to people with special interests, such as sports fans, racing and automotive fans, medical or other professionals, people with political or religious preferences (e.g., Hindu, Jewish, Christian, Muslim, etc.), people with medical conditions (e.g., HIV , obese), or those living in rural farm communities.
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.
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.