Technology has strongly changed the way stocks are traded from a decade ago to today. Historically, stock markets like the NYSE are a physical location for buyers and sellers to meet and negotiate trades. However, in the 20th Century technological improvements in stock trading have made the physical location to meet irrelevant, giving rise to electronic trading.
Before the telegraph arrived in the 1850s, brokers would place agents on top of hills and buildings between Philadelphia and New York City with signal flags and telescopes to rely stock prices between cities in about half-an-hour. Homing pigeons were also used to transmit information.
Later on, “runners” in the 1860s would carry stock prices handwritten on large chalkboards from the exchange to brokerage offices, so that the brokerages would be aware of a stock’s price. The NYSE was referred to as the “Big Board” supposedly because of these large chalkboards.