How do you establish a new currency? Well it is easy, you take control over some area of land, by military force or by treaty with the present occupiers of it, then you declare that the people living there need to pay you taxes, then you decide what to accept those taxes in. And that's what it means for a government to "back" a currency.
Considering all of the uproar caused by the Newsweek article, if people knowing you have bitcoins puts you in danger, then I'd say it's not a currency I want anything to do with.
Yeah, if everyone knew I had £1,000,000,000.00 hidden under my mattress (and some mattress that would be), then I imagine my life might be under a little more threat than otherwise too.
Err, it is widely known, google "world's richest people". The difference is, as your sibling post pointed out, those people don't have it hidden under a mattress.
