From those I normally speak about Facebook most of them use Facebook to keep track of their children and/or grandchildren. A Facebook group of medical students mostly use the group during exam periods. In a recent article the authors did a systematic review. They selected 42 articles evidence-based studies on factors contributing to Facebook use. All of these studies examined a population sampled from undergraduate and graduate schools. These studies do not represent those Facebook users that mostly use it to keep track of their relatives.
After a description of all the possibilities with Facebook they started with the sociodemographic variables and Facebook use. All you can say about these findings is that these findings point to cultural and sociodemographic differences in FB use. Specifically, females and ethnic minorities appear to use FB more often than males and Caucasians.
According to this review the following personality characteristics were important for Facebook use.
the review of the literature on Facebook use suggests that a high level of extraversion, low self-esteem, high levels of neuroticism, narcissism, and low levels of self-esteem and self-worth are associated with high FB use. Frequent Facebook use is also associated with lower academic performance but possibly higher self-esteem and sense of belonging.
The authors propose and explain based on the existing literature that Facebook users can be divided in two categories. This proposed models consists of Facebook use motivated by the need to belong. This is the need to affiliate with others and gain social acceptance. The other motivation is the need for self representation. Which is meant by the need for a continuous proces of impression management. The authors suggest that these two motivations can be both present in Facebook users but they can also be the single cause for Facebook use. These needs are influenced by a host of other factors, including the cultural background, sociodemographic variables, and personality traits, such as introversion, extraversion, shyness, narcissism, neuroticism, self-esteem, and self-worth.
Based on these assumptions the authors propose several new questions for research on Facebook use. For instance the influence of societies on Facebook use. Collectivistic and individual societies might differ in their Facebook use as hypothesized by the authors. In collectivistic societies might show a greater need to belong, while individualistic societies encourage self representation.
Ashwini Nadkarni, & Stefan G. Hofmann (2012). Why do people use Facebook? Personality and Individual Differences DOI: 10.1016/j.paid.2011.11.007