Here is the video version, if you prefer it:
What is the difference between the superuser and the regular user? The superuser (also known as root) has some extra privileges on the Linux system. (Ward, 2014) For example, if you are a regular user and you try to modify some system files, you will most likely not be able to save them and get “Permission denied” error. That’s because system files are only accessible by the superuser.
So the superuser is the most powerful user on the Linux system. Other users aren’t as powerful (meaning they can’t modify some files and can’t execute some commands). But guess what – that is good. “How can that be good?”, you might wonder. Well, imagine you downloaded a malicious piece of software that tried to modify your system files and you are logged in as a regular user. When the malicious piece of software tries to modify some system files, it can’t, because a regular user can’t modify them, you are running the program as a regular user and thus the malicious program can’t modify the files. I am not an expert in information security, but I remember this example being tossed around in some of my college classes, so I decided to put this in.
Hope this helped clarify the difference between the superuser and other users.
References
Ward, B. (2014). How Linux Works: What Every Superuser Should Know (2nd ed.). No Starch Press. Pages 9-10