Well, for one, WW2 affected virtually every country in the world and so it brought together a lot of countries from all over the world which may not have otherwise gotten close.

The destruction caused by the war meant many countries needed to import food/supplies and to make international trade easier, the Bretton Woods Agreement laid the foundation for modern international trade (and eventually things like the WTO would spring up out of it)

Likewise, the economic vacuum in a lot of countries gave rise to multinational corporations from the US and Europe who saw opportunities to expand into countries that wanted their goods. You've probably heard of stories of American GIs with Hersheys candy bars and American cigarettes bartering their goods with locals in foreign countries - that, in a way, generated demand in those countries for American goods.

From a social perspective, the advances in aviation and telecommunications during the war spurred the ability for people to connect with one another around the world. In other words, the "world shrank" for people.

Additionally, don't forget that western media expanded greatly in the post-war period. A lot of it was ideological - after all, the world was rapidly being divided between the western US-aligned countries and the eastern USSR-aligned countries.