Can anybody stall Bitcoin for 72BTC per hour? ANSWER: NO

[johnyj]

Could this attack itself partially initiated by large mining pools? Because they get part of the spam coin back through fee, it does not cost them too much, but it will make lots of coins on market occupied during the attack, thus raise the exchange rate. With more and more coins trapped in unconfirmed status, the coin supply on market will become less and less, a great help for the speculators who are pumping up the price at the same time

[Cryddit]

I note that this "stress test" coincides with a rise in price and an increase in "buy" volumes on major exchanges.  

Amid all the digital dust caused by unconfirmed transactions, someone (or more likely someseveral) is buying massive amounts of bitcoin.

I wonder if the current "attack" is being done by (or on behalf of) big buyers.  It would be intended to occupy the news and speculation while a move that would otherwise set off a more major price spike gets executed.  Pure conspiracy theory, of course.

Note:  As I write this my memory pool shows 74,581 unconfirmed transactions, which is 181 megabytes of backlog.

[Cryddit]

Alternatively this could be someone trying to prevent a (VERY LARGE) zero-conf transaction from getting into the block chain.   By design that attack shouldn't work, because a VERY LARGE transaction would inevitably rise in priority during a single day until it were included in the "freebie" section.  That is, in fact, why Satoshi put a freebie section in the block composition code in the first place.

But now that we have a bunch of miners ignoring the freebie section, sellers are at least theoretically vulnerable to it.  Which, essentially, means the advice about always waiting for at least a couple confirmations is essential.

Cryddit

[phelix]

I had always thought of someone with a big put option on Bitcoin but these would work, too:

Could this attack itself partially initiated by large mining pools? Because they get part of the spam coin back through fee, it does not cost them too much, but it will make lots of coins on market occupied during the attack, thus raise the exchange rate. With more and more coins trapped in unconfirmed status, the coin supply on market will become less and less, a great help for the speculators who are pumping up the price at the same time

The risk for a panic seems pretty high. Otherwise it could simply be large pools trying to create a proper fee market.

I note that this "stress test" coincides with a rise in price and an increase in "buy" volumes on major exchanges. 

Yeah, a whale trying to buy low. But it would make more sense to wait with buying until the problem surfaces, maybe even sell a bunch to create a panic.