Tranfering data between computers in different locations was started as a military computer science experiment. Today as our technology evolved, data communication become information backbone of our society.
The little boxes we call modems, routers and switches were all born from a need to connect teletype machines together, transferring information started at slow 25 bits per second. At that rate, downloading 1MB might take about 4 days. But we download even full HD movies in real time on ffew hours in on .