If a system were ever implemented that allowed exchanges/businesses to refuse to accept coins because at some point in the past they were tainted I would never again accept btc for payment. I would sell all that I have that are not tainted and never use Bitcoin again. I seriously doubt I'm alone in that regard. Could you imagine the Dollar surviving if you could have your money confiscated because some kid bought a bag of pot five years ago with the money in your pocket!
I agree. A widely implemented taint system would be the end of Bitcoin for me.
Most people don't understand 'taint'. Or 'tarnish' which was probably invented to help understand, but made things worse. It is perfectly possible to compute the percentage of a transaction which had a 'bad' history. So, your idea to ruin everything would only have the effect of ruining everything by a tiny fraction. And you your $1 might be worth $.95 due to the 5 year old pot purchase. Better than $0 though, right? And we solve a lot of crime after all.
The first sign that you are retarded - you assume that we are OK with someone else deciding for us what is "Crime" and what is not crime. In some countries, a pot purchase is a crime, and in some countries, it is not. So now we are going to let the Bitcoin Taint Council/Algorithm determine what is and what is not a "crime?" We've just lost a good majority of Bitcoin's function which is to remove political corruption and control from the money supply. Money is money, not a political tool.
And also it would be difficult to make an algorithm which was able to characterize 'bad'. For this we need a trusted body consisting at least partially of humans (until great strides are made in AI) to decide how bad is bad. These people will need compensation as will the infrastructure they operate to perform the calculations and communicate with the rest of the network.
The second sign you are retarded - you assume that there is a universal system of "bad" and "good" and that it is OK to [essentially] render someone's money worthless because an algorithm or "trusted body" (LOL) decides that selling pot is a crime, or transferring money across international borders without declaring it is a crime, or prostitution is a crime, or not reporting income to a government who will use 11% of it to kill people in the middle east... you get the point.
This is a law-making body for Bitcoin and nothing more. Good luck convincing people to accept this. Don't feel bad. Someone in the audience insisted on making an ass out of himself by not getting it (twice!) in the QA session.
Seems the only person who doesn't get it is you
It is said to be a 'bad idea'. It actually works fine. I've done it. It seems like a bad idea for the recipient unless he knows what he's doing. I don't see any real dis-advantages for the person giving up the funds. I mean, they are assumed to be a total loss by the nature of the transaction.
Again, a "trusted body" is deciding upon the nature of that transaction. When a "trusted body" gets to decide whether or not my coins can be spent because they were received in a pot sale, an assault rifle sale, well, there are other coins; I suppose that's the nature of the free market, right?
It's so GREAT that y'all have figured out a method to make the Bitcoin WORSE THAN the U.S. dollar!
Over 3/4 of US Dollars have cocaine residue but I can still spend them just fine. Just make coins that were used for transactions YOU DON'T AGREE WITH worthless! I'm talking about gray area stuff, by the way... the vast majority of people will agree that assassination markets and child prostitution are "bad" but what about selling guns in places where the gov't bans guns... what about selling drugs in places where it's legal, or places where it's illegal... what if someone operating a prostitution service in a jurisdiction where it is legal, gets his coins mistakenly "TAINTED" because what he is doing is BAD? Will he have to go appeal to the central governing body of bitcoin tainting and fill out forms and hire an attorney and wait 10 months to get his coins removed from the centralized taint list? What if I perform some web design work for Sea Shepherd and the Centralized Bitcoin Taint Organization considers them an "eco-terrorist" organization (after heavy lobbying by the Norwegian government) and freezes the coins they paid me? Now I have to hire a lawyer and appeal to a board or an algorithm to get my coins back, good luck because they are from a "Terorrist organization." Bitcoin Taint Organization gets to decide what groups are terrorist groups and what aren't. Is the Syrian government a terrorist organization worthy of coin taints, or the Syrian Rebel groups, or both, or neither? You seriously think this is a "good idea" and it "works?"
There is absolutely no way to guarantee (1) that the Taint Council's subjective morality won't end up screwing over lots of people, (2) the Taint Council won't taint coins unknowingly received that were used for "illegal" purposes 5 transactions ago (maybe 5 of my coins were from PirateEat40) (3) the Taint Council won't be corrupt and subject to outside influence from companies, governments, wealthy individuals, etc.
This won't end well for Bitcoin or for anyone who owns bitcoins.
EDIT: This is exactly what Paypal does.