A recession can be viewed as too little demand for goods & services (nominal GDP). One way for a country to bring itself out of recession is to depreciate its currency (which effectively moves GDP, via exports, to the country in recession from other countries, boosting the former’s GDP). However the problem with the current global recession is that this is not an option as there is too little demand for goods & services across the globe. A country cannot just devalue itself out of a global recession. Japan has just given us an excellent example of what happens when a country is too reliant on exports, as demand has contracted globally, Japanese exports have just fallen off a cliff (down nearly 50%) and Japanese GDP has contracted as a result (when the world finally recovers from this global recession both Germany & Japan are likely to try to grow the size of their domestic economies so as not to fall into this trap again). What is needed is for the global pie of nominal GDP to be expanded.
Welcome to Worldwide Quantitative Easing. If every major economy stimulates its own nominal GDP by convincing their independent central banks to print money and spend it by purchasing government bonds (the governments then spend the borrowed money on goods & services) then the result will be the desired expansion of the global pie of nominal GDP. The side effect is a round of currency devaluations which show up most noticeably against any country which doesn’t engage in QE (the Euro is leading this particular pack and the usually-conservative Swiss recently decided they did not want their currency to appreciate alongside the Euro so they intervened to lower the Swiss Franc against the Euro and embarked upon Quantitative Easing of their own to boost their GDP and underline to the FX market that they meant business). Also, as mentioned in Race to the Bottom (27 March 2009), real assets increase in value (as measured in fiat currencies) - admittedly real estate & equities are currently in bear markets but they won’t last forever, especially at this rate.
The question of whether the world’s central banks are capable creating just enough inflation but not too much can be left for a while.  The central banks will have to err on the side of creating too much inflation in order to be on the safe side – then they can rein inflation back in again by slowly taking the punch bowl away so as not to undermine the recovery.