Cyberspace can be huge and scary. In fact, it can be considered as several parallel worlds if you count the number of tools and platforms that are used by each person in the physical world. Of course, not everyone is living in these parallel worlds and those who live there can be categorized into two groups of natives and immigrants (referring to the nice talk by David White on Digital literacies).
Natives have more courage and confidence to use the tools actively, leaving the footprints, and enjoy the interactions with each other. While immigrants would rather keep the low profile and be more like an observer and enjoy reading and watching in the shadow.
From the other perspective, some people might not feel safe and comfortable sharing their personal information and would rather publish only their work-related information on the designated platforms within the relevant communities. I personally think that by increasing the cyberspace population, more and more people are considering the separation between private and professional life, thanks to the tremendous number of available platforms.