I am very uncertain why this millisecond trading is so important. What in the market makes this a viable way of doing business? Appearantly most bids in the market has a lifetime of 3 ms or less and are never realized. To me this seems like a way of manipulating the market. Personally I think available bids or offers should be secret. Only realized deals should be common information. This way it would not be possible to affect the market without cost. E.g. by leaving a bid or offer just to withdraw it milliseconds later.
Another thing I am uncertain off is how a buyer and seller is matched? When I leave an offer to buy shares for a specific price. What happens next? Anyway, I think these are important aspects to understand whether highfrequency trading provides a real value or not.