Lovely overview of HFT,
Noahpinion: A healthy side effect of High Frequency Trading?: "High Frequency Trading is nearly universally reviled. The Tournament Externality is just too obvious; it yields no social value to bring a piece of information to the market 1 millisecond before it would otherwise have arrived, but people are apparently spending lots of money in an effort to do so. It can't be efficient to commit our best and brightest minds to beating each other to the punch by 1 millisecond. Because of this, many have suggested a small Tobin Tax to curb HFT. Others have suggested"
'via Blog this'