As the European Central Bank (ECB) launched its broad-reaching bond-buying programme - the euro has sunk to almost an 11-year low, trading at less than 1.15 against the US dollar.

Chart live-tracking the euro against the USD, finviz.com

European stocks have been boosted by the announcement - hitting a seven-year high. Germany's DAX is at a record level. Italian shares also enjoyed a significant spike.

If Fed QE was a bazooka, ECB QE is a bazooka with a 500-page operator's manual without which you can't work out how to fire it. #risksharing

— Richard Barley (@RichardBarley1) January 22, 2015

This programme comes with strings attached - these purchases will be performed by national central banks - but 20 percent of the purchases will be covered by risk sharing mechanisms.

There are also limits on how much debt from each euro zone member the ECB can buy. The central bank will not buy more than 25 percent of new debt issued by any one country - and no more than 33 percent of a country's outstanding debt.

This can be read as a concession to German concerns that the program would be used to bailout struggling euro zone countries.