When using a traditional brokerage, the investor calls up his broker and places an order. The broker calls the post on the exchange floor right away and the transaction has been taken care of. When using an internet brokerage, the investor must log on, place his order and click the button on his mouse to send the order. Hard to say, some broker is responsible for the investor's market order, but the investor does not know who. Placing a market order on the internet is also quick, it does not take much time for the investor, but the investor is left with uncertainty about how long it will take before his order has been transferred to the trading post of the exchange floor.
Traditional brokerages have the full advantage of real time communication with the investor.
The fact that the investor actually talks to his broker adds security to the investor. Some investors are less secure about their decisions than other people and feel more safe when talking to the broker. Most traditional brokers sit with information right infront of them, with live updates from the exchange floor to ensure their cusomters that they have correct information. The huge advantage of online brokerages is that they provide all kinds of statistics and information about different securities within just a few mouse clicks. Looking up a stock's price over the last month, with moving averages and trading volumes, takes only a few seconds for the investor, but there is no communication between the investor and the broker.