gen2 //In many computer languages, comments are preceded by an exclamation mark to tell the compiler/interpreter that it is to be ignored. //
I was talking about the use of exclaimation marks in message boxes. For example "Printer is out of paper!" or "File Not Found!". I don't see the why every communication with the user needs to be exclaimed.
Many? That would be an overstatement. HTML and XML use the exclaimation mark as part of their comment tags.
However it is not involved of comments in any of the other significant modern programming languages and I don't know of any that use it alone to indicate a comment. It is used as the Not Operator in some.