I can't speak for the totality of the world, but I know that in Western Europe it was primarily seen as a cotton shortage, while in Egypt it was seen as a goldmine, as Egypt's government forcibly switched almost all of the countries considerable agricultural might toward the making and selling of cotton to Western Europe. This led to a great deal of profit for Egypt, but was a bad move in the long run (turns out food is a good thing to have).

Source: "A History of the Modern Middle East", by William L. Cleaveland

Broadly popular opinion was in favour of the North and elite opinion for the south. The cotton mill workers of Lancashire boycotted southern cotton exports because of slavery even though they knew it would hurt them economically. Interestingly this probably contributed to the working class getting the vote in 1867, but that is another story.

But the elite view was with the south they were seen as romantic defenders of property against a individualistic and commercial north. For example, Queen Victoria Viscount Palmerston, Gladstone (again Chancellor) and Lord Russell, whose statements in support of the South contributed to years of hard feelings in the United States expected the South to win.

Interestingly enough, Pope Pius IX was, according to Robert E. Lee, "the only sovereign... in Europe who recognized our poor Confederacy". In 1863, Pius IX had sent a personal letter to Jefferson Davis with an autographed picture of himself. He even went as far as to refer to Davis as "the Honorable President of the Confederate States of America", which led the Union Congress to formally cut diplomatic relations with the Vatican in 1867.

I've always found this fascinating. The fact that the Pope didn't even remain nominally neutral when every other European power did is a true anomaly in history...

Sources: 1 2

While Serbians may not have been too interesting in the war, other Western powers most certainly were. Probably the most interested among these were France and Britain, who traditionally have stakes with the United States. The South continually called out for foreign intervention, particularly from Britain. Leading up to the civil war, the South was a huge exporter of cotton, primarily to the British. Many felt like the threat of an embargo alone was enough to get Britain to send the South aide. I don't have any sources about Latin American interest in the war, but given the U.S.A.'s history of policing the Western Hemisphere and simple proximity, I can't imagine that they weren't at least following the War.

The main source I have for this is just my highschool U.S. history textbook, The American Pageant.

If I can give an example - I am reading a Serbian newspaper from the period, and all I can find is dry reporting of the events.[1] It doesn't seem that the war caused a lot of attention.

it was hugely influential in the formation of the Canadian government. It was seen as a failure caused by too much power in the states hands so Canada was organized with a strong federal government and weak provinces. It was also thought that too much democracy led to the war, so the Canadian senate was made up of appointed persons who could temper the democratic lower house, the head of state stayed the British monarchy.

It is amusing to note that a few powers left to the provinces, natural resources other then precious metals, health care, and education, were not considered important at the time, but are hugely important today.