eHarmony is not your usual online dating site. Unlike Match.com or OkCupid, users do not get to browse tons of profiles to see if there is someone they might like. Instead, eHarmony does the choosing for you, sending you a limited number of "compatible matches" — candidates the site's proprietary algorithm thinks will make a good match. The company also differs because it aims at people who are looking for long-term relationship or even marriage, not those who look for casual dating.
To successfully match people who are looking for a long-term relationship, eHarmony needs not just a lot of people in their database, it also needs people who are ready for a long-term relationship. This seems self-evident, but cluttering up the site with those looking for something else will increase the noise-to-signal ration and make matching harder. In its everyday business, eHarmony does an excellent job by discouraging potential customers who may not be so serious about dating. They ask potential members to complete a very long questionnaire of more than 250 questions.