The exchanges in which stocks and other securities are traded serve an important function in finance. They bring together people interested in buying and selling securities in order to create a universal price. Brokers and dealers are also an important part of the system, their methods and standards are ultimately behind the success of the exchanges. Many information innovations have advanced the functioning of exchanges, going all the way back to the ticker machine, which was created to communicate the price of securities at a point in time to all interested parties. Electronic Communication Networks and automatic exchanges, more generally, have significantly impacted the exchange of securities and few exchanges still have physical trading floors.