Zach Schonfeld serves up some fun facts from Shady Characters, Keith Houston’s new book on the history of punctuation:
The asterisk (*) and dagger (†), for instance, grew largely out of the symbols the grammarian Aristarchus of Samothrace placed in the margins of works of Homer to note lines of questionable origin; the em dash (—) nearly drifted into neglect when typewriter keys forced typists to turn to the double-hyphen (–) instead, but was subsequently validated by modern word-processors. And the Internet plays a tremendous role in the drama as well: the octothorpe (#), for example, fell into obscurity before Twitter resurrected it as the devilishly popular hashtag.
In other words, Houston’s Shady Characters covers a tremendous amount of historical and topical ground—veering from ancient Greece to a 1960s Madison Avenue exec seeking to jumpstart a new punctuation mark, from the Protestant Reformation (Martin Luther’s Ninety-Five Theses played a minor role in the development of the asterisk) to online communities, where numerous would-be pioneers have proposed an irony or sarcasm mark. (A huge success, obviously.)