Some sites provide free registration, but may offer services which require a monthly fee.

Other sites are more specific, based on the type of members, interests, location, or relationship desired.

A 2005 study of data collected by the Pew Internet & American Life Project found that individuals are more likely to use an online dating service if they use the internet for a greater amount of tasks and less likely to use such a service if they are trusting of others.

Some sites such as Ok Cupid.com, and are free and offer additional paid services in a freemium revenue model.

Some sites are broad-based, with members coming from a variety of backgrounds looking for different types of relationships.

Research about social networking reveals that the online dating services driven by subscriptions offer the least amount of social networking opportunities.

The dating services modeled on the free-at-the-point-of-use model scored much higher as many of them utilized the Circle of Friends social networking method and a wider number of online community genres.

A German documentary analyzed the market and uncovered multiple problems of online dating sites.

Amongst them are "romance-scamming" (persons registering on the sites to get money from people falling in virtual love with them), using controllers or animators registered with multiple fake accounts, using unexpected and sometimes unlawful conditions in the terms and conditions leading to longer contracts a client intended to sign.

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.

In Germany government financed NGOs like "Verbraucherschutzzentrale" sometimes help to sue online dating sites.