"Story" is the use of word, image and/or sound, in any medium (print, web, film, video, novel, art, etc.), to narrate an experience, typically with an emphasis on emotion, character and insight. As cave art tells us, storytelling has been essential to human communication since before recorded history.
Public storytelling is story made widely available, with the potential to influence individual opinion and community and national policy. Story stands in contrast to exposition, the straightforward conveying of information, such as the standard "hard news" piece that is a journalistic mainstay.
"Public square" is any place that a story can be shared: a newspaper, magazine, book, website, blog, song, broadcast station or channel, street corner, theater, conference, government body and more. The American origins lie in the colonial village square and the first presses, which published the pamphlets and newspapers that advocated the birth of a new nation.