its not even one person, or one specific group. just a bunch of underground people who copied the idea. some groups or people might know others who did the same thing, other times 'anonymous' groups/individual efforts were completely unrelated to the others.
Who said it was a guy? Who said it was a gal? I do believe it is a blanket statement. It can also mean a person who doesn't want to be known by a name given to them from someone else. There are so many possibilities. I could go on forever.