Some sites provide free registration, but may offer services which require a monthly fee.
Other sites depend on advertising for their revenue.
Most sites allow members to upload photos or videos of themselves and browse the photos and videos of others.
Sites may offer additional services, such as webcasts, online chat, telephone chat (VOIP), and message boards.
Online dating sites use market metaphors to match people.
Users of an online dating service would usually provide personal information, to enable them to search the service provider's database for other individuals.
Members use criteria other members set, such as age range, gender and location.