Learning all the time...

Learning is so cool. The Internet rocks!
I have wondered for some time about the terms "The 1st World" and "The 3rd World".
I vaguely understood that we were part of The 1st World along with Australia, the U.S.A., Britain, etc. And I conceived of The 3rd World as being less well developed nations like some of the countries in Africa, Asia and the Americas. However, I hadn't heard of a 2nd World and wondered who that might include if it did exist.
Well, today I found out thanks to Wikipedia. Read on for a simple explanation:

From Wikipedia, the free encyclopedia

"The three worlds as they were separated during the Cold War era, each with its respective allies. First World: the United States and its allies. Second World: the Soviet Union and its allies. Third World: Non-aligned and neutral countries.

The terms First World, Second World, and Third World were used to divide nations into three broad categories. The three terms did not arise simultaneously. After World War II, people began to speak of the NATO and Warsaw Pact countries as two major blocs, often using such terms as the "Western Bloc" and the "Eastern Bloc". The two "worlds" were not numbered. It was eventually pointed out that there were a great many countries that fit into neither category, and in 1952 French demographer Alfred Sauvy coined the term "Third World" to describe this latter group; retroactively, the first two groups came to be known as the "First World" and "Second World".

Some countries did not fit into these partitions, including Switzerland, Sweden, and the Republic of Ireland, who chose to be neutral. Finland was under the Soviet Union's sphere of influence but was not communist, nor was it a member of the Warsaw Pact. Yugoslavia adopted a policy of neutrality, and was a founding member of the Non-Aligned Movement. Austria was under the United States' sphere of influence, but in 1955 the country became a fully independent republic under the condition that it remain neutral. Turkey and Greece both joined NATO in 1952, but are not predominantly in Western Europe. Spain did not join NATO until 1982, towards the end of the Cold War and after the death of the authoritarian dictator Francisco Franco.

As many developing countries have industrialized, the term Fourth World has been coined to refer to countries that remain predominantly agricultural or nomadic and lack industrial infrastructure. However, such coinage can create confusion because Fourth World is used by scholars to refer to stateless nations (such as indigenous nations in the Americas). Countries that were previously considered developing countries but now have a more developed economy are grouped under the term Newly-industrialized countries or NIC."

- http://en.wikipedia.org/wiki/First_World