I'm referring to this page: http://www.interactivebrokers.com/en/p.php?f=smartRouting If I'm on the bid in, say, BAC on IB, and I put that bid there using their smart routing algorithm, will they put me on the bid in those dark pools they are referencing? Does my order "exist" in multiple locations, or do they just sort of pick which slot to stick me in on the best conditions at the time? And when I am on the bid there, do I get preferential treatment on my fills compared to non-retail agents trading on that desk, or am I at the back of some mysterious dark queue? How do I know exactly where I got my fill? Moreover, can I choose to strictly be on their dark pools instead of using their smart routing algorithm? e.g., I have a thin stock and I want to get out of 10k shares, but don't want to tip the players off that I have large size. Moreover, if I'm on the bid on BAC, would they also match me against another customer of theirs and give me a cheaper rate, or do they strictly put me in some other venue? In other words, am I competing for the fill with some faster, professional market maker when I get routed to these "special" locations?