The Americas had sporadic dealings with Africa, Asia, and Europe who were an entire ocean away. Interaction between the eastern and western hemispheres was random and irregular. Although they were not in much contact with the eastern hemisphere, the Americas set up large empires and widespread trade just as the east had previously done.
The people of Australia and the Pacific Islands had even more isolation than the Americas had. Asian trade networks occasionally reached the Philippines, Indonesia, New Guinea, and very few regions of northern Australia. This was the only interaction that the Oceania region experienced.
The people of the Pacific Islands sailed across the ocean, creating passages and connections to other island group, but they wandered to the continents bordering the Pacific Ocean. There were very few natural resources available, and extremely limited land, however the island groups still created organized agricultural societies and chiefly.
Although isolation did not set the Americas and Oceania Region back too much in terms of organization and development, there are some dangers that come with it. For example, the Americas were isolated which made them an easy target for invasion. Even though it may not be true, when you have little contact with other countries or continents, the are likely to jump to the conclusion that you as a group are underdeveloped and underpopulated. These are green lights for people to come invade because they assume that you have no military or political structure, making you easy to overthrow. This era was also an era of a necessity for land expansion and exploration, and if there are areas that Africa, Asia, and Europe do not know much about (due to lack of contact), they will jump on the opportunity.