As the most traded currency in the world, the USD obviously commands decent trading volumes on this pair as well. The USD is a major, while the DKK isn’t one. The USD/DKK pair is not a major in its own right, and it is not a commodity pair either.
The USD started the floating trend back in the 70s, and it is the world’s top currency by trading volumes as well as by popularity as a reserve currency. The USD is so interweaved with the “bloodstream” of the world economy, that more of it is held outside the country than within. In addition to the US, scores of other countries use the USD as their official or de-facto national currency.
The reins of the USD are in the hands of the Federal Reserve, which controls the relative value of the currency by adjusting the lending interest rates.
The Danish Krone – in its current shape – was introduced shortly after the end of World War 2, in 1949. Its predecessor had been pegged to the German Mark used by the Reich. Being an EU member, Denmark pegged its currency to the Euro, via the European Exchange Rate Mechanism, but it has thus far stopped short of actually joining the Eurozone.
The DKK is a very services-focused currency: over 65% of Danish GDP originates in this sector. Industry and agriculture round out the number, which explains why the DKK is far from being a commodity currency.
Trading the USD/DKK pair doesn’t really make a lot of sense given the close correlation between the DKK and the EUR. One might as well trade the USD/EUR, the results would indeed be the same. There are no carry trading opportunities and commodity-prices do not influence the equation either.