From the 'Bloomberg Surveillance' feed:
Adam Posen, former Bank of England board member and now the president of the Peterson Institute for International Econoimics, says private money like the virtual currency bitcoin "has a very unstable history." Posen talks with Bloomberg's Tom Keene on Bloomberg Radio's "Bloomberg Surveillance."
A little context: Adam Posen, until last year was a voting member at the Bank of England, arguing repeatedly for even more money printing. Needless to say he is fully supportive of the bitcoin project.
<warning> This one might make a few of you rage...</warning>
Note: I'm not sure how long Bloomberg keeps their rss feeds up, so this link might break soon.