I think this article does a good job of illustrating why its so hard to have an open dialog on this subject. Start with asking "What is front running."? The

I think this article does a good job of illustrating why its so hard to have an open dialog on this subject. Start with asking "What is front running."? The market's definition would not include what HFT do. But bring this up to someone without knowledge of the public markets and their first reaction is to say, hey this is front running, it must be wrong. "Front Running" has a specific definition and it only relates to a broker and their own clients. You trading before me because you are faster is not front running. You understanding my flow is not front running. You can then ask "What is public information". The fact that everyone can see any tape they pay money to see so there doesn't seem to be any one acting on "insider knowledge." Now tell people that HFT's will use their fast machines to change their orders due to a change on one exchanges tape before the main NBBO tape is updated and some people will claim that this is obviously wrong. The other argument I've seen made here is that trading on "insider knowledge is obviously wrong." Well it isn't obviously wrong and the entire commodities market assumes that anyone can trade legally on insider knowledge. Imagine you are the biggest producer of oranges. You know that you are going to have a bad crop so you but some orange futures so you can meet your demands. This is insider information you've traded on and its the way the market is intended to work.