Over the weekend PayPal froze the accounts of both Morpheus and CoinPal, two online exchangers that sold bitcoin. In taking this step, PayPal is making it clear that they intend to view bitcoin as a full-fledged e-currency and not just a reusable proof-of-work "math puzzle". Ultimately, the enforcement relies upon PayPal's Acceptable Use Policy, which prohibits transactions that are associated with money service business activities, including currency exchanges. So, the real surprise here is that, at least according to PayPal, bitcoin is now a currency. Undoubtedly, this decision will have implications in future legal cases against bitcoin.
PayPal has continually strayed further and further from their original mission of providing an global extra-governmental system of digital currency based around privacy, strong encryption, and e-mail addresses. Most recently, it was decided by PayPal that Wikileaks was not worthy enough to receive donations that utilized its payments platform. Apparently, these unfortunate incidents are part of a long history of PayPal deciding who should and who should not get paid. In 2004, the Daily Pundit blog and the civil liberties TalkLeft blog received letters from PayPal informing them that their accounts would be frozen unless the blogs removed controversial and "offensive material". From Reason's book review by Rodney Balko:
That's a far cry from the libertarian vision founders Peter Thiel and Max Levchin originally had for PayPal, an online payment service that enables account holders to send money to anyone in the world with an e-mail address. Thiel and Levchin had hoped PayPal would grow to become an extra-governmental system of currency, something reminiscent of the world described in Neal Stephenson's novel Cryptonomicon, in which programmers use encryption to create an offshore data haven free from government control."
The Morpheus closure announcement can be found here and the CoinPal closure announcement can be found here.