This article is surprisingly good. I like the mention of Bitcoin being the "world's first" decentralized digital currency. This is a clear way to convey to the reader that Bitcoin very is different from everything else. I use the same term in my Bitcoin introduction: http://blog.zorinaq.com/?e=66
The Economist author only made one error: Bitcoin is not the only decentralized digital currency. Some forks exist (eg. Litecoin), although they have very little traction currently; see the Alternate Cryptocurrency board: https://bitcointalk.org/index.php?board=67.0