A billion seems to be an important number.
When the number reach to the levels of billions, the richness is totally another level. The degree of life can jump to another level.
This might be why ancient India philosophy estimated that the age of the universe is in billions.
Living in a new culture of a different language, what you need to learn to make yourself equal to the native speakers: at least 1 billion times of what your know previously.
Within the same culture, go from a normal native person in the culture to a person who enjoy the culture on a very high level, you need to expand at least 1 billion times.
The population of human civilizations reached billions. That makes a huge difference. It is about to jump to another level of richness.
The number of computers connected on the Internet has reached billions. That is about to create another level of degree of life on the web, as we are witnessing now. Because of it, our social space is about to increase by billions.