Online dating services generally require a prospective member to provide personal information, before they can search the service provider's database for other individuals using criteria they set, such as age range, gender and location.
Online dating sites use market metaphor to properly match people up. Most sites allow members to upload photos of themselves and browse the photos of others.
Sites may offer additional services, such as webcasts, online chat, telephone chat (VOIP), and message boards. Some sites provide free registration, but may offer services which require a monthly fee. Other sites depend on advertising for their revenue. And some sites are free and then offer additional paid services in a freemium revenue model.