Blogger Felix Salmon at Reuters has a nice explanation of Thursday's trading failures and what it could mean looking ahead.
He sums up by saying, "It's been a very impressive day to learn how the stock-market sausage is made: I think we just saw the largest intraday fall, in point terms, that has ever happened. But the bigger lesson is that in the short term, any market can fail temporarily. The question is whether the jitters from this afternoon are going to mean increased volatility and risk aversion going forwards. My feeling is that, yes, they both will and should."
By tomorrow morning we should understand more about what happened and a whole bunch of trades likely will have been cancelled. But traders in Asia certainly aren't treating North America's trading problems as a buying opportunity caused by computer glitches. Markets are down two to four per cent there. Friday morning the U.S. jobs number will do a lot to determine what kind of day we'll have. Any whiff of weakness and we could be in for another rout.