Some sites are completely free and depend on advertising for revenue.
A great diversity of online dating services currently exists.
Some have a broad membership base of diverse users looking for many different types of relationships.
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 number of tasks, and less likely to use such a service if they are trusting of others.
It is possible that the mode of online dating resonates with some participants' conceptual orientation towards the process of ﬁnding a romantic partner.
Profiles created by real humans also have the potential to be problematic.
For example, online dating sites may expose more female members in particular to stalking, fraud, and sexual violence by online predators.
Still others rely solely on paid membership subscriptions.
Opinions and usage of online dating services also differ widely.
Most services offer digital messaging, while others provide additional services such as webcasts, online chat, telephone chat (VOIP), and message boards.
Members can constrain their interactions to the online space, or they can arrange a date to meet in person.
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.