How has the use of Facebook evolved since its creation?

Normal use of the social networking site Facebook has evolved in two primary ways. The first main transition is one from intimacy to publicity. The second is from direct to broad communication.
 
Intimacy to Publicity
When Facebook was created, its intended use was for college students within the same college to be able to connect and share with each other. From there, it expanded to connect college students from many different colleges. After that, Facebook for high school students was added, and soon after, it opened to anyone over the age of 13. 
 
At the start, Facebook was a tool to connect with people you knew well. As it developed, criteria for connections became fewer and fewer as users could connect to an increased number of other users that are further removed from one's daily life. This expansion was visible in the increased number of Facebook friends a person might have. While initially, your Facebook friends closely reflected your friends in daily life, friend lists quickly expanded to include acquaintances, co-workers, classmates and others known on a shallow level only.
 
Direct to Broad Communication
Initially a tool to contact and communicate with others, Facebook has evolved into a space in which one-on-one communication is no longer the primary objective. Instead of sharing messages with friend or posting on a friend's wall, a primary function of Facebook now is to share with a broader audience: your entire friends list. Instead of sending a one-on-one message or wall post, users post items such as links or photos on their own walls. These posts have no single intended recipient, but rather an intended audience.