I just noticed, so if anyone cares, I'm going to comment.
It's about the history of "Shazam!" Superman came out and sold well, as did Batman and others. Many companies followed suit with their own characters. ("The Green Hornet works? Introducing the Blue Beetle!") Fawcett came out with Captain Marvel. He became more successful than Superman because Fawcett played to their fanbase. Superman was an adult reporter. Captain Marvel was a young boy. Which story does a young boy want to read? Correct!) When DC found out CM was outselling Superman, they buried Fawcett in frivolous nuisance suits to bankrupt them. Fawcett went under. Then the copyright on the name "Captain Marvel" lapsed. (Marvel Comics found out, and rushed out "Captain Marvel", the story of the Kree Captain Mar-vell, so they had a captain with their comics company name.) Then DC bought the rights to some of Fawcett's stuff.
The original character of Billy Batson, Captain Marvel is now public domain. Virtually all his print stuff is not, and DC owns it. They started printing his comic, but were unable to print "Captain Marvel" comics since Marvel owned that copyright. So, the character could still be CALLED that but the comic could not. So, they named the comic "with a magic word....SHAZAM!" That, of course, was also the name of the old wizard who gave Billy and the others their powers as well as the magic word. They came out with titles like "the Power of Shazam!" and so on.
People keep getting them confused, so it's no shock if DC renames Billy Batson or Freddy Freeman as the superhero "Shazam." (Freddy, formerly CM Jr, completed "the Trials of Shazam" to become "Shazam.")
So, the old TV or movies of him are called "Captain Marvel", and the later stuff (70s onward) are called "Shazam."