I'm still confused... I thought the USA was the 'New World' - or was that Australia?

Eastern Bloc?  Crikey... so many worlds to choose from...

I think I'll stick with the term 'poorer countries' and leave it at that (although then there's the question of what truly constitutes 'rich' and 'poor' depending on your value system....)

Argh!   

3rd world has come to mean undeveloped

That's why I refer to the USA as "second", not "first". Everytime I'm over there I'm really wondering about the infrastructure (like streets etc.) in the "Leading Economy of the World" 

[ducksforcover...]

@ShadySue, I was attempting to be generous.

I have been to parts of the world where the culture is so backwards and the governments so corrupt that it will probably be several hundred years (if ever) that these areas will catch up.

Hardly what I would call developing.
It is a catch-all phrase that elevates those countries where the people have nothing but dirt to eat to the same status as China which actually IS developing at an amazing rate.

I actually heard the term "second world" on the radio this morning - I was listening to the BBC world service (in the US) and they used it in a story about some in Croatia not wanting to join the EU. There's a referendum coming up, I gather. I'm fairly sure they were referring to Croatia and the countries around it as second world.