Such companies offer a wide variety of unmoderated matchmaking services, most of which are profile-based.
Online dating services allow users to become "members" by creating a profile and uploading personal information including (but not limited to) age, gender, sexual orientation, location, and appearance.
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.
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.
Other sites target highly specific demographics based on features like shared interests, location, religion, or relationship type.
Online dating services also differ widely in their revenue streams.
Introduction sites differ from the traditional online dating model, and attracted a large number of users and significant investor interest.
In Eastern Europe, popular sites offer full access to messaging and profiles, but provide additional services for pay, such as prioritizing profile position, removing advertisements, and giving paying users access to a more advanced search engine.
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.
Some sites are completely free and depend on advertising for revenue.