On the Facebook platform, a connection displayed between two users indicates that they share one or more contacts in their respective friend lists. This shared contact signifies a degree of connectivity within the social network. For example, if User A and User B both have User C as a friend, Facebook will present User C as a connection between User A and User B.
The display of shared connections provides context regarding the potential relationship between individuals. It can offer a sense of familiarity or trustworthiness, facilitating social interaction and network expansion. Historically, this functionality has been a key element in assisting users to identify and connect with individuals within their existing social circles, both online and offline.