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.
Members use criteria other members set, such as age range, gender and location.
As online dating's population becomes larger, sites with specific demographics are becoming more popular as a way to narrow the pool of potential matches.
The 20 most popular dating sites in 2006 as ranked by Hitwise include j (for Jewish singles), Christian Mingle.com, Christian Cafe.com, Man (same sex introductions), Love From India.ini, Black Christian People Meet.com, (for Latino singles), Asian People Meet.com, and (for Indian singles).
Some sites provide free registration, but may offer services which require a monthly fee.
Other sites depend on advertising for their revenue.
In Germany government financed NGOs like "Verbraucherschutzzentrale" sometimes help to sue online dating sites.