Either pay for it (some expensive while others low cost) or use Free Online Ads.
Whether you are in any of the continents in our world, advertising has the same impact or effect.
Post Free Ads in Africa, Antarctica, Asia, Australia, Europe, North America, and South America would mean reaching to the world.
There are 6.7 billion people in this planet earth. Internet is reported to have hundreds of millions of websites and e-commerce is expected to break the staggering trillion dollars. Advertisement is definitely an important tool to promote any product, services or even just news or announcements.
If there is any global news worthy to be publicized it is this information that needed for local and world impact. Speed, cost, flexibility all are to be taken into account for any business.