10 years ago on 4chan's Comics and Cartoons board, buried within the hourly pony thread, a new word was formed. Or at least became mainstream. "Brony" was born, and with it the continued growth of one of the most ridiculous fandoms on the internet.
Over the years it has been both a beacon of celebration and a giant cringe bullseye, but it has certainly stuck around and made us more noticable.
Along with that, Derpy was first discovered and screencapped on the same board, becomeing somewhat of a fandom mascot. She too had her ups and downs over the years with Hasbro's kneejerk reaction to an angry email about her appearing in the show, and eventual return as a permanent character later on once they reversed their stance on her. Yay for the derp!
Thanks to Squeaky_Belle for the heads up