How is this 'laundering'? Laundering is putting dirty money into some system and getting clean money back. This appears to be just giving some bitcoins away and getting nothing back. Forgive me if I'm misunderstanding something.

[edit: okay, paulcole just beat me to the punch.]

I don't understand why every hacker tries to come up with a novel way of laundering bitcoins or tries to launder them all at once.

Is there something urgent they need to spend thousands of bitcoins on right now that they can't just launder a hundred bitcoins a day through tumblers over the next few years?

You're assuming that they have a vested interest in holding their Bitcoins for some greater good.

I don't know how you came to that conclusion.

My assumption is that they're selfish assholes who want to successfully launder stolen Bitcoins. Holding on to Bitcoins and laundering them through tumblers gradually would allow them to do that. But it seems like every time a thief steals a large amount of Bitcoin, they try to put it through a tumbler all at once or come up with some other scheme that doesn't work to launder it all at once.

Just curious, how is he laundering them? Wouldn't he need to get clean bitcoin back in return?

The idea, I think, would be the analog of throwing thousands of dollars from a bank robbery into the street. The stolen bills can be identified by their serial numbers, but if law enforcement tries to crack down every time they see one of those bills pop up, the actual thief will be buried in the noise.

In Bitcoin land this is both more feasible and more complex at the same time -- it's very easy for a poorly planned version of this to make the thief no harder to identify, and even a well-executed version requires vigilance in the future to avoid betraying the identity of the thief vs. the identity of one of the giveaway recipients.

I suppose he could pose as the "winner" and claim ignorance, although I'm sure there's much better ways of laundering via a Mixing service [https://en.bitcoin.it/wiki/Mixing_service] or something similar.

Presumably he will send some/all of the coins to himself (plausible deniability).

Or maybe, you are right, he is not directly attempting to launder, but just "creating noise" in the block chain to make it hard for investigators to trace the stolen coins.

Is it possible to verify that these coins are among the ones stolen?

Yes, and his coins turn out to not be related to the hack: http://blog.zorinaq.com/bitfinex-hack-2016/