The world is most often referenced as the earth and everything in it. However, it can be also used as or in reference to the people in the world, a group of people or things, or a new environment.
This covers many topics that bloggers may write about that apply to or are of interest to many people including world news, world politics, world organizations and world charities. Other worlds outside of earth, within our galaxy or the universe are also interesting topics. World leaders are often in the news as their decisions greatly impact our world.
Bloggers see that the world outside is full of natural beauty, birds, animals and trees and and environment which is different than what we're used to.