The free market response suggests that MtGox may suffer anyway, however, the mob psychology of the bitcoin traders is that if MtGox comes back up, they will probably start using it, maybe at high volume, or maybe at low volume.  There will be a mass exodus to TradeHill however, but, I am not at all sure that TradeHill is prepared for THAT rapid of an expansion.  Maybe they are preparing for it during the halt in trading; but I am not sure they have load tested their system at anywhere near the volumes of MtGox [nor am I sure that they have not ].  The better TradeHill does responding to the new comers, the less likely MtGox will recover the overwhelming dominance of the volume of trades that it had previously [as a percentage of the market as a whole].  This all assumes MtGox even survives.  I have already posted that they have a problem with rolling back "half trades" meaning that if somebody traded currency for bitcoins and withdrew the bitcoins to their secured wallet during this time then MtGox will have to come up with that amount in bitcoins [not currency] to roll back the trade.  Do they have enough?  Anybody even have an idea what that amount might be?  Most were legitimate trades, many of which were reacting to the market adjustment to the illegal activity [selling on the way down is the downfall of risk averse investors and thus they shouldn't be trading bitcoins purchased with cash .. mined coins might be considered differently due to the cost of actually acquiring them in the first place, but I digress], but that is a free market response [which is why the exchange should not be tampering with it, but instead, paying for the losses of those affected by their lack of security resulting in the theft of their property].  Either way, since the price dropped as a natural [to this market] reaction to a crime and not a more fundamental cause, I think that as long as people can trade, the price will recover rapidly if not almost immediately when trading is in full swing [well, can maintain volume to the point of satisfying most traders enough to continue with bitcoin as opposed to abandoning them for whatever they can get].  Probably there will be a bit of volatility due to low volume at first [due to MtGox not trading for awhile at least .. my supposition and TradeHill taking in much of the slack, but not ready to take on the high volumes at once thus spiking the price for the few that like to trade on volatility [adrenalin junkies buying and many of those selling have large supply of bitcoins to take advantage of the spike with low relative risk ].  I think it all hinges on volume in the few days following when trading restarts [and an imminent restart of trading at that].  TradeHill holds all the cards; if they are up to the task, they may split the market with MtGox assuming MtGox survives [and they seem to be quite resilient and nobody knows the extent of their outlay if the follow through with this stupid rollback; or for that fact, what it would cost to payback the victims accordingly if they do not do the rollback].

It will be interesting how it plays out, but the mob has proven fairly predicable (mostly "gut" ... said "emotional" based trading) for the most part, which is making some people rich I suspect [since they can see almost precisely when and why an event will happen ... except the crimes of course].

If anything I have written is some or all not agreed with by anybody, there is one thing that nobody can deny; the need for more stable and significant exchanges (and maybe the only reason why I don't want to see MtGox go dark at this point).