One of these is that people now move around more often for work, distancing themselves from friends and family members who could play matchmakers.Another is that they are living longer, and hence more likely to look for new love later in life.The spread of fast broadband connectivity in many countries has also encouraged people to dabble in online dating.
In countries and cultures in which arranged marriages are common, sites such as India's Shaadi and Bharat Matrimony, which boast many millions of clients, are a big hit with young people who want to influence how their marriage partners are chosen.
And a number of sizeable digital matchmakers, including Jiayuan and Zhenai, have risen to prominence in China.
Deepak Kamra of Canaan Partners, an American venture-capital firm that has backed several dating services, including Zoosk and Bharat Matrimony, estimates that the industry's revenues from membership fees and advertising now amount to $3 billion-4 billion a year.
Searching for that special someone In addition to broad-based matchmaking sites such as Match and Zoosk, the online-dating world has also spawned thousands of niche ones.
Some, such as JDate, which is designed for Jewish lonely hearts, and Ave Maria Singles, which focuses on Catholics, serve specific religious or ethnic niches.