Ok, I'll give it a shot:
let's say you wanted to buy a huge number of coins in the near term, but the ask volume means if you buy them all at once, the end price is more than you want to pay. How do you shake some bitcoins loose from the ask tree?
Maybe, you buy ~1/2 of what you mean to buy in one fell swoop, and then put up some large bids and wait.
People sitting higher up on the ask side think "Hm, looks like the activity has peaked and may start to go down. Nice looking bid wall going, guess I'll grab some quick profit." and proceed to sell to the exact same whale that started the whole thing off.
Which raises the question of exactly how many more coins does the whale actually want to buy and at what price. I think if they have a target price north of $135, there are going to be some very unhappy bears soon.
(If my past prediction record is any indication, this means you should sell immediately.)
That's my guess; the whale(s) are buying about a million $ a week. That's probably all that they trust on Gox at one time. The pullback on Gox is pretty natural after the kind of runup we've seen, OR maybe it is just that arbitrage is finally happening. This whale put up that wall at 135 because that was his average buy in price. He put it near the money. HE WANTED it to be eaten. He WANTS coins.
The whale is NOT supporting the price during the week. He is happy to disappear for a week and hope the price goes down. This is the behavior of a real long term investor...
Right now, I think it is very risky to sell. But at the same time, there's lots of coins being mined and in theory these ASIC owners need to sell to recoup their investment. There may be a large hidden ask at this price and this whale is only eating half the generated coins per week... but of course there are a lot of smaller investors adding demand.
