I just know the textbook stuff- that it takes order from the politicians (ex: obama and the congress could ask for a trillion coin, pretty please), can be forced to buy government debt, and as a goal of helping employment.
I'm most familiar with the european ECB : by construction it follows a monetarist policy (M3 grows at a fixed 4.5%), is independent of political power (you can't ask it to mint a trillion coin for you), and doesn't care about employment.
Before 2012, it also could not be forced by politicians to buy "toxic assets" like sovereign debt (greek debt anyone?), so they created the european stability mechanism, guaranteed by the "federal" EC budget to do this very same thing!
It is even better : now they are not forcing the ECB to buy sovereign debt on political orders, they buy sovereign debt by themselves!
http://en.wikipedia.org/wiki/European_Stability_Mechanism
Could you please elaborate on the US situation? (I'm checking wikipedia at the moment)
If the Fed is a private bank, and I understand correctly your Rothschilds example, that makes the situation in the US similar to the one of the Bank of France prior to 1945 when it was nationalized - it was a private bank, with a monopoly on sovereign currency emission.
Only it's even better and more lucrative, because the Bank of France had to deal with the gold standard (even in the 1929 great depression) while the present day FED is doing fiat money.
Who are the FED shareholders who get to benefit 6% returns, backed by the US government? How do you compare that to the french situation before WW2?