eHarmony
Founded by Dr. Neil Clark Warren, eHarmony is responsible for thousands of marriages and engagements. Their success is because they are focused to deliver matches that have the foundation of compatibility necessary for a lifetime of joy. eHarmony has a comprehensive relationship questionnaire that is one of the key ways they screen singles for deep compatibility.

Match
As a proven leader in online dating services, Match.com offers millions of profiles to meet your match. Their online dating sites and affiliated businesses cover six continents with more than 30 dating sites in 18 languages.