Social media has an impact on one's personal and family life. It can also affect one's behaviour. The extent of the impact depends on each individual, but it goes without saying that it's worldwide reach has a significant lcoal ad worldwide impacts.
Most of our contacsts on Facebook, Twitter, etc aren't people with whom we have any personal contact. This means that not knowing personally the people we can have negative consequences. As for example: to replace your identity, to have photos and videos of you, to know where you live, what you are doing in that moment...etc.
I think that the forms of communication that exist today are quite good with regard to several years ago. Now, there is much more privacy in your photos, in your personal data...etc. Although there are hackers who can get all that, but only professional hackers.
In conclusiom, means communication such as Facebook, Twitter, WhatsApp and online games are now safer than several years ago. But you have to be careful with hackers who can get all your information.