Besides photographs, each user's profile could include any number of personal details including age, height, weight, education, marital status, number of children, and smoking and drinking habits.
According to Pew Research, 15% of American adults report using online dating sites or mobile dating apps.
Online dating has jumped among adults under age 25 as well as those in their late 50s and early 60s.
Rather, a recession is a significant decline in economic activity spread across the economy, lasting more than a few months, normally visible in real GDP, real income, employment, industrial production, and wholesale-retail sales.
For more information, see the latest announcement from the NBER's Business Cycle Dating Committee, dated 9/20/10.
A team led by Elizabeth Bruch, a sociologist at the University of Michigan, Ann Arbor, tapped into this torrent of dating data.