Relationships start with a period of courtship: on Facebook, messages are exchanged, profiles are visited, posts are shared on each other’s timelines. The following graph shows the average number of timeline posts exchanged between two people who are about to become a couple. We studied the group of people who changed their status from “Single” to “In a relationship” and also stated an anniversary date as the start of their relationship. During the 100 days before the relationship starts, we observe a slow but steady increase in the number of timeline posts shared between the future couple. When the relationship starts (“day 0”), posts begin to decrease. We observe a peak of 1.67 posts per day 12 days before the relationship begins, and a lowest point of 1.53 posts per day 85 days into the relationship. Presumably, couples decide to spend more time together, courtship is off, and online interactions give way to more interactions in the physical world. —The Formation of Love.