I wonder if this is somebody really being philanthropic, or if they just control a ton of bitcoin that they can't access (for fear of taxation / Questions Being Asked), so they drop it on charities they're sympathetic to...
The donor has said/intimated they they have enough money from bitcoin that they own that they really dont need the rest and so it may as well go to good causes. He/She/They can probably expect something of a tax write-off but I imagine that taxes arent really a problem for them either. If you are happy to give away ~$80m then paying ~$10-20m in taxes is not going to phase you.
In the US, there's a limit to how much you can deduct in charitable donations from your tax obligation, and IIRC it's something like up to 20% of your taxable income. So unless PF has a taxable income > $56M * .2 (or whatever the actual amount is), they'd get very little tax benefit to making it rain this much. Assuming, of course, that they're in the US.
The donor has submitted patches for one of the open source projects that they have funded. I imagine that it would be possible for someone to identify him and further the source of the coins could be identified if they were, for example, related to a hack or Silk Road, even tumbling them (tricky with such large volumes) would be noticeable. There is a permanent ledger showing where they have been.
I kind of like to think there are people out there that really think and live according to that phrase "because once you have enough money, money doesn't matter".
I know I would...
Obscuring the source won't help if the IRS knows "John Doe at least once controlled the Bitcoins at address foo". At that point, they'll assume you still control them unless you can prove otherwise.
Unless the money came from an illicit source (I don't think the source was stated, but making a ton of money from Bitcoin's rise is perfectly legitimate), cashing out would surely be perfectly legitimate as long as one paid the right taxes, which there would hardly be a reason not to.
