Traits

There are small villages around the world. 

World Population: 1,000

There is no civilizations on the planet. 

Handful of towns and many villages.

World Population: 1,000,000

Many towns and villages scatter the world. There are some major cities that have high volume of the population. 

World Population: 1,000,000,000

There are many sentient beings living on the planet.

So many cities, towns, and villages. If one were to travel they would have many choices of great places to pick from. 

World Population: 1,000,000,000