“CoinValidation’s plan, if successfully implemented, would presumably lead to the blacklisting of some coins based on their past transfer history (e.g. having at some point been sent to/from deep web contraband marketplaces, paid as ransom to malware operators like those of CryptoLocker, stolen, allegedly ‘laundered’, associated with scams/ponzis, etc). In effect, this would destroy the fungibility of bitcoins. Some ‘clean’ coins would be easier to spend and transact with, while other ‘less clean’ or downright ‘tainted’ coins would be more difficult to use. The case Hew Crawfurd brought against the Royal Bank of Scotland in 1749 had the potential for similar ramifications.”
http://www.reddit.com/r/Bitcoin/comments/1qomqt/what_a_landmark_legal_case_from_mid1700s_scotland/
Tip Freedomwat.ch Staff with Bitcoin