what happened during the crash by my understanding was basically this:
someone had collected a lot of bitcoins, some stolen, but perhaps some of their own as well, and by a lot i mean more than 100,000 coins (of a total float less than 7m)
mt.gox has withdrawal limits of 1k / day and 10k / month so that they don't run afoul of money laundering laws... whoever this person was had well in excess of 2 mil in bitcoins at the time thus making it impossible for them to withdraw. so what did they do? they put huge resting bids at .00001 with a different account and then sold the entire other account as a market order, filling a lot of resting bids on the way- but primarily to fill themselves at fractions of a penny and then instantly making a withdrawal request to get all of their coins out (100k+) at .00001 cents per so that it was under the 1k withdrawal limit. at this point it is unclear if they were successful or not because mt.gox has only said "not that many coins were withdrawn before the site got taken offline" and quoted the 1k / day limit--- making no reference to what bitcoin price the 1k withdrawals were taking place at.
some of these coins may have been stolen, but i'm not entirely sold on that as you'd have heard of more peoples accounts being emptied to get a sum that large and so far i've only heard of one large theft (25k bitcoins).
as far as how this will affect the market going forwards, i'm not all that worried- i plan on trading btc intraday and only holding cash each night... so i don't really care if over the long term btc fails as an idea (which i don't think it will) i just love the intraday volatility- and it isn't going to be less after this move.
and as far as everyone being shocked at the first "main" exchange for a currency that is widely accepted by hackers getting hacked? shocker?? to a certain extent it is better that this happened early on (and actually was no fault of the site it was an auditor's computer that got compromised) so that more security is now being enabled. that's ok though i hope none of you come and trade it because it is too scary- i'll be all alone trading a product with 30%+ intraday moves every day- i'll be lonely on the beach drinking my pinacoladas.