      The only disadvantage associated with the SNET method of execution isthat it is not mandatory. The advantage to the trader is that he or she caneffectively step around a "herd" of traders attempting to execute trades atthe market. For example, a trader who is long stock can do this by offeringstock below the inside bid, effectively crossing the market to get out of along position that is quickly running to the downside. The trader can alsobid for stock above the inside ask for an equal but opposite result. Whenmarket makers get preferenced outside of the inside market, they are moreinclined to fill the order because it is arbitragable. The market maker canbuy shares from you below the bid and sell them at the inside bidimmediately, or sell stock to you above the ask and immediately buy themback at the inside ask.