Fair bit spoken about it on ShareSene about computer algorithmic trading concerning Petsec (PSA)
NightStalker
"We can't stop it, so I guess the trick is to take advantage of it.... when they are sucking the price DOWN, that's the time to buy in - as long as you're sure that the signs are there such as a series of small trades. But you have to beat the other computer to the punch. I've done it - but sometimes you'll find that the number you think you're bidding for suddenly disappears in a trade."