The algorithm depends on a new metric the researchers are calling "dispersion," which looks at connections between people who have different sets of friends. Close friends are likely to share a lot of friends in common, which social scientists call "embeddedness." But people in romantic relationships tend to connect each other to different spheres: for example, a husband is likely to introduce his wife to his work friends, college buddies, and members of his kickball league, with whom she may not have any other connections in common.