Still others rely solely on paid membership subscriptions.
Introduction sites differ from the traditional online dating model, and attracted a large number of users and significant investor interest.
In Eastern Europe, popular sites offer full access to messaging and profiles, but provide additional services for pay, such as prioritizing profile position, removing advertisements, and giving paying users access to a more advanced search engine.
While some sites conduct background checks on members, many do not, resulting in some uncertainty around members' identities.
For instance, some profiles may not represent real humans but rather "bait profiles" placed online by site owners to attract new paying members, or "spam profiles" created by advertisers to market services and products.
Over 50% of research participants in a 2011 study did not view online dating as a dangerous activity, whereas 43% thought that online dating involved risk.
Because online dating takes place in virtual space, it is possible for profile information to be misrepresented or falsified.
However, Sam Yagan describes dating sites as ideal advertising platforms because of the wealth of demographic data made available by users.
There are mixed opinions regarding the safety of online dating.
Such sites earn revenue from a mix of advertising and sale of additional options.
This model also allows users to switch between free and paying status at will, with sites accepting a variety of online currencies and payment options.
Other sites target highly specific demographics based on features like shared interests, location, religion, or relationship type.