This paper has two aims. First, it studies the extent to which personal networks on Facebook are “actual". Second, it attempts to explain the closeness of Facebook relationships in real life, based on data collected from Facebook. The analysis involves the personal networks of 112 Australians aged 50 and over, collected from Facebook using an application called AuSON (Australian Seniors’ Online Networks). The findings from the first part of the analysis indicate that Facebook personal networks are to a large extent actual. More than 60 percent of participants reported that more than half of their family members and close friends are on Facebook. Participants could also identify closeness of relationship with almost all of their Facebook friends and on average, 50 percent of these relationships were close or very close. The second part of the analysis involves multi-level regression models, and it is found that the structural characteristics of personal networks have the largest explanatory power (in terms of whether a Facebook friendship is close in real life), compared with other variables such as social similarity based on socio-demographic characteristics, geographical proximity and type of relationship (kin/non-kin).