This is simply the techie in me but is it not possible to track all block chain transactions using forensics (NSA, CIA..etc)?
Even Darkcoin, Monero, Boolberry and the like make some type of digital footprint on the Internet that is trackable.
In my mind, l33t hackers will always be one small step ahead of the NSA and the NSA will always be miles ahead of the general populace.
I don't know enough about the governments abilities to know what the NSA can do and I don't think anyone else here does either. I know it's possible to parse the blockchain and get trails from it that most people wouldn't think possible.
I have a simple rule you can follow that makes this problem moot. Don't do anything on-line or buy anything on-line that you wouldn't show your mother and grandmother in church on Sunday Christmas morning. If you must buy drugs or some other illegal item please only use fully anonymous U.S. Dollars. For further security I suggest only purchasing items on a university campus where all items are readily available.
Snowden has given us a pretty good idea as to what the government is capable of doing (as of ~2 years ago based on technology that was available then), which is pretty much anything.
I would only assume that the technology available to the government is only going to increase over time
