The NYSE is the largest stock exchange in the United States. Nearly 2800 listed companies trade here, with a global market capitalization of $15 trillion.
Investors have two ways to trade, one is to contact the stock trader through the Internet to place an order, and the other is to "execute" the trade through their own manager on the stock trading floor.
Small transactions are often done automatically on the Internet, and large trades often involve communication and judgment, and are more likely to be executed by traders in the NYSE's lobby.