NITE's (as well as SCH's, Dempsey's, etc) market making segment has experienced quickly dropping revenue capture per share. Sure, vol has decreased, but are there other long-term forces going on to decrease their profitability? How is trading from a principal basis (without enjoying the monopolistic setup of an NYSE specialist) changing? Why not just send an order to agency based ECN who isn't going to screw with my order? Not clear to me why principal based markets maker are going to be able to hang around for long.