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.
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.
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.
Since 2003, several free dating sites, operating on ad based-revenue rather than monthly subscriptions, have appeared and become increasingly popular.
Several newer sites such as Ok are beginning to offer more full featured dating services for free, and are starting to compete with staples in the free dating site world such as
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).
At the end of November 2004, there were 844 lifestyle and dating sites, a 38% increase since the start of the year, according to Hitwise Inc. By 2007, many prominent studies show that Baby Boomer interest in online dating have soared.