Dr. Jessica Vitak at the University of Maryland is an expert on how people use social media and how it affects their relationships. In recent research, she has shown that Facebook is a valuable tool to help people maintain relationships that might otherwise fade.
A lot of us probably have these people in our Facebook friend lists. I know I have a bunch of cousins and high school friends who I talk to regularly online. None of them live near me. I have only see a handful of them in the last fifteen years, and among those, there have only been a couple meetings. Without Facebook, I would have almost no contact with these people and the relationships simply would have faded away. With Facebook, I'm able to keep up on what they are doing, share comments or messages, and maintain a base level of interaction necessary to keep our relationships going. This is exactly the kind of interaction Vitak addresses in her recent work.
In her paper "Facebook makes the heart grow fonder" , she studies how people use Facebook in their relationships. In particular, she looked at people who were separated by large physical distances or who had little communication outside Facebook.
The core idea at work is this: "To maintain a relationship, partners must communicate with one another...The end of a relationship occurs when people stop communicating” . Facebook allows communication in a variety of ways. Aside from direct interaction through chats and messages, Facebook supports light weight interaction, through likes. It also allows passive communication in one direction. When a person posts a status update, that communicates with all the friends who can see it. Thus, two friends are communicating about their lives, even if it is only through status updates that are broadly visible.
In her study, Vitak found that when people are geographically separated, they tend to rely more on Facebook to communicate and keep up their relationship. Similarly, when people who are weaker relationships (e.g. casual friends and acquaintances) use Facebook as their primary means of interaction, they engage in more relationship support than people who have other ways to talk to one another. These Facebook-communicators also believe the site is more valuable to the maintenance of their relationships.
Vitak sums this up as follows: "You may think Facebook has little value beyond entertainment, but the results of this study suggest that Facebook helps extend the lifespan of many more relationships than would be possible without the site--and maintaining those relationships may benefit you down the line."
So don't feel bad next time you get on Facebook to look up your long-lost friends. Connect with them, send messages, and open the communication that helps relationships survive. It may be different on Facebook than when you interacted with a person offline, but it still works.
 Jessica Vitak. 2014. Facebook makes the heart grow fonder: relationship maintenance strategies among geographically dispersed and communication-restricted connections. In Proceedings of the 17th ACM conference on Computer supported cooperative work & social computing (CSCW '14). ACM, New York, NY, USA, 842-853.
 Dindia, Kathryn. "Definitions and perspectives on relational maintenance communication." Maintaining relationships through communication: Relational, contextual, and cultural variations (2003): 1-28.