Everyone has a history in building its own social network, I think everyone does that before Internet appeared, but in a different way. I build my social network, mainly through participating at conferences, projects and trainigs, while looking for the best individual that fit my values and my interests. I dont believe in the wide network influence so, diversity may count in a particular way. Another way to develop the seocial network is online, mainly through facebook, and linked in.
I see myself as reticent in sharing personal experiences in online environments. As I said, the network will be resilient if you planned or think before creating your network. I guess that the principles and values in wich you base your network will make it sustainable and closer to your needs.
Maybe dangers are everywhere but if they are well managed, it shall be easy to cope with them.