To an extent people have separate lives online. People sometimes feel more free to say and do what they want online verses real life because some of the pressure of being face to face is taken off. People can keep who they are hidden or have a fake profile, or they can simply feel more relaxed because they are safe at home.
I think that the lives of people can be separate on the Internet and in real life, to some degree. There are some situations where it is hard to keep the two separate, like Facebook, but there are some sites that can be separate from real life. Some of the sites I think are separate from real life are forum sites, anonymous blogs, Youtube, and similar sites.
Either people on the internet are being way more brash and honest than they would ever dare be in real life, or they are pretending to be another person entirely. There is a double life with the internet. I very much doubt that there are many who are telling the absolute truth.
People do not have separate lives on the Internet and in real life. Any life a person has online is also part of their real existence. They may not choose to show it to other people, but it is still in their everyday psyche and in the actions they choose to take every day.
When the Internet was mostly anonymous it was easy for people to live separate lives on the Internet and its still possibly today, but far less likely. Most people don't live a life on the Internet although they may post things about their real life on social media. I don't think the two things should be confused. I someone going to me more likely to celebrate the good or the bad? I know I favor the good things.