Darkcoin wasn't mentioned in the article, but it is the one cryptocurrency that seems to be gaining favor explicitly because the transactions are untraceable (not to mention nearly instantaneous). At least two or three markets seem to be accepting it along with a bunch of legal websites like gambling websites (where both privacy and speed are appreciated). Had Ulbricht been using Darkcoin (not that he could have... it was only introduced last year), the FBI could not have relied on the blockchain to catch him. It will be interesting to see if Darkcoin continues to gain adoption.