If 80% of bitcoin sites unrelated to each other are down at once, there's obviously some sort of attack going on. Several unrelated sites (but sharing a common theme) don't normally go down ... unless there's an Amazon outage :P (which there wasn't..).

The question was, whether the DDOS was caused by a large volume of trades. The answer is, no, because there wasn't a larger than normal volume of trades occurring, it wasn't possible due to the lag on the exchanges.

I don't know why all those bitcoin sites were down, but the fact is that the largest bitcoin sites were all down for at least a few minutes each.

The intention though was probably to trigger a market reaction to buy in at lower prices. It appears to have worked temporarily.

I still don't understand why they would bother spreading their attack volume across multiple sites. Hitting Mt.Gox with everything they've got offers two potential strategies:

- trigger a crash, buy low, stop the attack and watch it go back up

- trigger a price drop and profit massively from arbitrage with other exchanges still trading higher(BTC China for example)

This doesn't follow in the event of a run.