Follow-up on this afternoon's gap down in the market

Regarding today's afternoon plunge, a CNBC commentator notes that at first traders on the NYSE floor thought it was a bad print. Then traders believe that a series of trades were queued up against the curbs, and when the curbs were released, then the Dow gapped down another 200 points in a matter of minutes. Says traders have never seen such an instantaneous gap down... It's worth noting that at least for the moment, the Dow seems to have held its initial test of its Dec low of 12,090 (see 15:08 comment)... Dow down ~400, S&P down ~44, Nasdaq down ~86.