With early investments in social media companies such as Twitter, Tumblr, Foursquare and Zynga, Fred Wilson has become one of the world's most watched angel investors. And one of the opportunities he is watching most attentively is the emerging industry of digital money.

"To cure its addiction to debts, the United States has to re-establish the common sense principle that one should live within its means."

Whether the gold price will continue to rise will depend not just on whether faith in fiat money continues to decline, but on whether the search for an improved form of money will produce, as we should all hope, something not just as good as gold, but better than it.

A different version of dollar collapse, described by analyst and trader Jim Rickards in his book, Currency Wars, comes complete with deliberately wicked foreigners.

spending by America's Federal Government (adding in state and local governments significantly increased the total) was around 24% of national income whilst tax revenues were 15% of national income. That left a near-record peacetime budget deficit to be financed by borrowing of 9% of GDP.

when there is a mixture of 'good' coins with high silver content and 'bad' coins that have been clipped or debased circulating, the public will hoard the valuable good ones and pass on the bad ones to others.

Social websites such as Second Life and even Facebook have experimented with creating their own currencies. But the most interesting innovation so far has been the launch in 2009 of bitcoin, a digital currency with an encrypted soundness algorithm designed to allow the supply of bitcoin to grow in a way that is mathematically inflation-proof.

For a hard-core group of gold bugs fiat money is in so much trouble it is a matter of urgency that the world should return to the system of gold-backed money that dominated the global economy at the end of the 19th century. Much of their argument — made by the likes of the Gold Standard Now campaign — rests on gold's track record over many centurie

Today, gold bugs talk about gold having been money for millennia, which is actually rather misleading. For most of human history, the metal that was typically used as money was silver. By contrast, gold was too rare to be widely used in a liquid market (a necessary condition for a commodity to be money). Silver was more abundant and deposits of it