What exactly do the market makers in Nasdaq Stocks do? Do they fill orders for their clients, and if so, WHO are their clients? Do they trade for their own account on the side, at the same time? Also, there are over 4000 Nasdaq Stocks ... how many stocks does your average MM watch, or is the majority of stock trading done by a computer, most of the time? I'm just wondering what the REAL STORY behind the market makers is ... anyone know, anyone care to tell us more about a day in the life of a Nasdaq MM?