As for the second article, it says "Bitcoin is unstoppable without end-user prosecution." Well, duh,…
It's not quite "duh" - the original Napster and eGold died because the US Government could prosecute those who ran the services, at much lower cost (both monetary and electoral) than prosecuting enough users of those systems to kill them. It's a point worth making that Bitcoin doesn't have a single central hub that can be killed easily.
Unless you're a rare expert ready to go to extraordinary lengths, there is no anonymity on the internet if the government is decided to come after you.
But there's practical anonymity in a large enough crowd.
I would be surprised to learn that most Bittorrent pirates took reasonable security measures, yet Bittorrent piracy is hard to kill due to its popularity and its decentralised design.
It's a point worth making that Bitcoin doesn't have a single central hub that can be killed easily.
Couldn't the government simply declare trading in Bitcoins illegal - if it so chose? If someone publicly says they accept Bitcoins, the government could do a sting-operation on them, to verify this - and then punish them. Users would pretty quickly be driven underground.
Tangential, but a subject of some local interest:
Why Bitcoin will fail by Avery Pennarun. "The sky isn't red." Thesis:
I'm not sure I buy these and am not competent to evaluate his claims on 3., but would like others' critique.
L019: Bitcoin P2P Currency: The Most Dangerous Project We've Ever Seen by Jason Calacanis. A rather more enthusiastic viewpoint of the project:
The actual text contains many more caveats than the eye-catching selection of points above.