I'm reposting this here as I believe it is relevant:
I love bitcoin and what it was created to be. But in light of the ability for regulatory authorities to ban or blacklist specific coins that have a certain address history association personally I see bitcoin as losing its fungibility in that respect.
Sure "Bitcoin is not the problem" is one way of looking at it, but other side of the argument is that "why not just fix that issue by disallowing transactions to be tracked by default and just have privacy features on by default?"
We know the answer: Too much opposition to changing the core protocol allow that to happen.
So the argument has those two sides...
SIDE A: Bitcoin is broken via fungibility because one can discriminate some coins to be accepted vs others based on block chain analysis.
SIDE B: Bitcoin is not broken and the financial system and businesses who choose to discriminate certain coins from being spent/exchanged in 3rd party businesses are broken (and the problem).
Two sides and probably both right in their own respect.
Although the arguments and sides exist it doesn't change the fact that businesses/govt/individuals can discriminate from accepting certain coins based on block chain analysis of their respective histories.
We have to remember that bitcoin does exist in this current world no matter how much we disagree with TPTB or the broken legacy monetary system. As long as that type of system exists there will be some issues concerning discriminating against accepting certain coins from certain addresses.
THOUGHT SCENARIO EXERCISE DEALING WITH COIN DISCRIMINATION
This thought experiment is to merely be just that an experiment and is not intended to give people ideas on what to do or not do in certain scenarios
You are an average joe looking to trade cash for bitcoins or some object like (gold coin) for bitcoins. Assuming you know each of the possible scenarios are true below.
BOB has bitcoins he wants to trade/exchange with you.
Which scenarios below would you consider not trading with BOB and discriminating against accepting his BTC for payment or trade?
Which scenarios would you trade with BOB and not discriminate against doing a trade?
BOB wants to trade you his BTC is the same person who just:
A. Robbed an old lady of her BTC by ransacking her house then beating the crap out of her.
B. Sold Kiddie porn for BTC
C. Ordered and executed a terrorist attack on a city killing a few hundred people and was paid in BTC to do so
D. Evading taxes with BTC
E. Was paid in BTC for prositution
F. Sold illegal drugs for BTC
Now if you really think about it, people can and will discriminate if they know or suspect something has happened with those BTC.
Would you accept BTC for trade or payment knowing that one of those things happened?
Which ones would you discriminated against more than others?
This brings in different shades of discrimination. As not every person would necessarily pick all of them to discriminate against. Some might even pick all of them to discriminated against. Some possibly would not care.
BTW I noticed you did not even address my thought example above.
How would you determine who you would trade with if you knew those things were true? Which scenarios would you trade with that person if you know that the scenario is true and BOB is guilty of doing that?Then the problem would not be "That money is bad" but it would be you not wanting you to deal with criminals, which is up to the law enforcement to catch. Or the individual to care.
Do you see anyone having problem buying or accepting the Bitcoins sold by the FBI? No.
You forget that TPTB (the authority) can pretty much do what they want. When they possess the coins from criminals it is all of a sudden made "clean".
Do you see exchanges using some sort of blacklist database considering BTC as bad? No.
YES. BTC-e and the evolution stolen coins.
MTGOX did this with bitcoinica stolen coins.
Bitpay is doing this on their own recently announced black list as I linked to in this thread once already.
Do you see some sort of centralized authority that track and detect all BTC used in criminal activity? No. And wait, its not even possible to detect/enforce, since bitcoin does not have a centralized authority.
So unless you have actionable example of your super project that isint even possible in the first place (Its effectively impossible to detect which BTC has been used for anything you mentioned or not, its impossible to enforce, etc) then we can safely say that we're at no risk.
There just is no way for a company to dedicate billions of USD trying to track and tag every single transaction ongoing when there's not even a way to consistently connect the BTC to a crime or even an identity.
TLDR; Its fungibility, even though its not even relevant with BTC, is assured because there is not way to say whether the BTC was obtained legally or illegally. Especially when you take into account how easily it is to mix BTC.
Just because you can't see something, doesn't mean it isn't there.
I'm pretty sure it won't cost billions to track and tag transactions that they want to.
How is there no way to consistently connect BTC to a crime when many people who operated on silk road got caught and thrown in jail? <---- this topic is irrelevant as we are not really talking about people getting caught in their crime but coins associated with a crime not being accepted for payment/trade.
Do you think Ross Ulbright could have benefitted from default privacy options in bitcoin?
Mixing BTC doesn't remove the transactional history. Thus coins can be traced back to their source on the block chain.