Many of the trades that Goldman Sachs erroneously placed through the New York Stock Exchange, the CBOE and Nasdaq have been or are in the process of being canceled by the exchanges.
Each of the exchanges has a set of rules governing when trades will be "busted" or "adjusted" because they are "clearly erroneous." You can read the NYSE rules here and the Nasdaq rules here. The basic gist of the rules is that when trades fall too far outside the prevailing market price, they'll be canceled or have their prices brought into line with the market.
So how often are the exchanges busting and adjusting? This seems an important piece of data to have in evaluating the quality of our markets. After the massive Goldman error and the glitch that crippled Knight Capital, lots of people are wondering whether the increasing complexity of our exchange trading systems is increasing the rate of errant trading.
But, it seems, none of those people work for the exchanges.