[shaftway]

The point isn't that an algorithm is doing it. It's that algorithms are actively poisoning the system with orders that couldn't possibly trade. By stuffing the pipe with these orders, timely information to other traders is delayed; the article states that the delay can be on the order of 30 seconds.

If I'm spending a half billion to colocate in an exchange's data center because it'll trim a few microseconds off my data transit time, I'd be pretty pissed if I was suddenly delayed by 30 seconds.

[tutufan]

Indeed you would. Which is why this sort of illegal behavior rarely happens. (Keep in mind that none of this is anonymous or forgotten--the exchanges and SEC know exactly who did what when.)