In the end, governments can not tolerate widespread use of cryptocurrencies. They benefit too much from the ability to print money in sovereign currencies to lose control. They will use whatever excuse sticks - child porn, money laundering, aiding terrorism... whatever gets the public on board with new restrictions.

I believe that's why we've seen article after article lately about all the horrible people using bitcoins, plus scare stories about bubbles and how You'll Lose All Your Money. Concrete legal steps are on the way.