There are plentiful examples of cult-like behaviour on many Social media platforms. Whether said cult behaviour is for gamers with undying loyalty to a certain game franchise or Anarcho-Communists organizing actions in their own dark corners, there is practically a "cult" to fit everyone's interests and beliefs. This is the basic nature of human tribalism in all its colors.
I believe that the internet, social media specifically, has become a new form of a cult. Everyone in the world is connected, and no one is truly alone anymore. Many people spend their whole lives on social media. I recently watched the movie The Circle and it really opened my eyes to how social media runs and controls our lives. Many of us are attached to our phones 24/7. We can use the internet for immense good, but at the same time, it can be used for bad. We spend so much time on social media, that many of us are no longer truly living.
When people starts to excessively use social media in their lives that the practice of sharing their personal information or browsing others life would deeply infiltrate their lives, these users could potentially behave like cult members. In fact excessive social media users does share a common ideology, that is to publicly share or view information about themselves or others so as to gain the acknowledgement of people around them. Social media also has a leader that every member is keen to be loyal towards, that is the likes and comment, which is the acknowledgement of others that has their information. Therefore, in some sense, social media may have brought people together through the sharing of information but excessive use of it may cause a serious problem with people's lives.
Trust me, I am aware of the cult-like behavior that goes on in social media, but the social media itself is not at all a cult. It is a platform that can host a cult. There's nothing inherently cult-like about social media, it's just that some people choose to use it that way.
A cult requires a shared (usually extreme) ideology among its members. No such shared ideology exists on the Web. Internet users are constantly bickering among themselves. Additionally, cults require leaders to obey. There is no "cult leader" of the internet, telling us what to think (although some netizens certainly hold more power than others).