A new blog about punctuations marks was just launched by Keith Houston. One of his first text is about the pilcrow. Keith reported to me that topics as irony mark will follow. Even another one about Interrobang? perhaps?
The pilcrow even appears in Microsoft Word, where it adorns a button which reveals hidden characters such as spaces and carriage returns.
Indeed, the pilcrow, or paragraph mark ¶ is much more than a symbol for hidden glyphs on text setting!