Arguably one of the first Web 2.0 sites because of its focus on connecting its users, eHarmony, an online relationship website, matches users together using a rigorous 250+ item questionnaire. It is popular and successful with well over 20 million registered users and 230 of its matched partners married each day.

eHarmony’s compatibility matching system determines members’ compatibility with others based on their values, character, intellect, humor, religious/spiritual beliefs and many other dimensions. With the understanding that people are much more complex than what a picture and short blurb can express, eHarmony submits each of its members to a very long, but worthwhile personality test.

Skeptics and naysayers may tout eHarmony as a disservice to relationships in general; however, it has spurred massive growth in the online dating industry which has grown to more than a billion-dollar sector. Until March 2009, the site offered only heterosexual matching services, and took serious criticism for this from the left.

Competitors include Dating Direct, Match.com, Matchmaker and friendfinder.