The Office of Foreign Asset Control (OFAC) announced on March 19 that it was considering including digital currency addresses associated with its list of persons and entities with whom U.S. persons and businesses are forbidden to transact business.
Full article on CoindeskHa ha. This is rich. OFAC doesn't understand that bitcoins are fungible. They can investigate, arrest and bring to trial those involved in illegal businesses, but they cannot really try to blacklist cryptocurrency addresses. Even if they try to do, there is no way they are going to impose their will on the rest of the world.