The console is used to give feedback of user input and display textual results of executed commands.
The concept originates from the beginnings of the IT world, where limited displaying capabilities were available.
The computers and displays were connected through low-speed serial ports and the monitors could display texts only based on built-in character-sets.
Nowadays everyone uses high-resolution graphical displays, so the console environments are emulated by the videocards.
Read more: http://en.wikipedia.org/wiki/System_console