I grew up in the age of newspapers and have many a fond memory of seeing character in pain shouting something like "$(%))#@#!" in my favorite cartoons. Little did I know that this typographical convention actually originated in American comics strips.
In October 2013, Slate
answered the question, "How Did @#$%&! Come to Represent Profanity?"
The author, who blogs at Language Log,
looked back and found the symbols dated back to the very early days of the comic strip, and were probably first used in "The Katzenjammer Kids," written and drawn by Rudolph Dirks, a German immigrant to the US. It was only in the 1960s that the term "grawlix" was coined to describe the #$&%& things. (Other terms, like 'obscenicons,' didn't stick.)
In fact, Language Log has a long and interesting series of entries on the grawlix and its many appearances in popular culture,
and they're pretty much all worth reading.
If you really want to fall down the rabbit hole and learn how this symbol also took root in non-American comics (I also have fond memories of seeing a grawlix or two in the pages of Asterix the Gaul),
visit the entry at TV Tropes
for all the faux-obscenity you might want.(What's this? It's a new type of column, giving you a heads up on articles and commentaries you might find interesting. We hope you enjoy!)