I believe the answer is:
The Affordability Of Cell Phone Service
The widespread availability of the Internet in homes
Before these two exist, it is difficult for people to obtain new information and contact other people in different regions. After the development, we could even easily contacted other people in different countries and the flow information could happen with one single touch from our hand
1 ly is a distance, defined as the distance travelled by light in a year. hence 2.5 mn lys away means it takes 2.5mn years for light to reach earth b/c light travels a distance of 1 light year in a year
In the 21st century, the extent of the development of technology is increasing exponentially. If this escalates even more, the world is going to be even more dependent on digital platforms. The most adaptable to this change are the young adults of this generation that are commonly referred to the Millenials. They make up the majority of the world, and therefore, the major market. So, businesses direct their advertisements on social media because their target audience are always online. By doing this, they are more exposed to the college-age people which could potentially bring profit.
