Adam etc, when will we see 390 again hehe..?
Also, how is it possible that if someone starts to dump on let's say Bitfinex. Bitstamp for some reason follows instantly (or the opposite)?
If you're selling you want to minimize your slippage, so you need volume. Instead of dumping on one exchange you split the dumping across multiple exchanges. And of course the other part (like with Mr 30k bearwhale on stamp) is arbitragers (sp?). Bots buy on cheaper exchanges and sell on higher for profit.