The status line is that lovely bar at the bottom of the screen that is used to display information. You can make it even more useful with some minor configuration tweaks:
" Always display a status line (it gets hidden sometimes otherwise). set laststatus=2" Show last command in the status line. set showcmd
If you want to go even further, there are plugins to enhance your status line. Powerline is an everything-in-one powerhouse, while Airline is its lighter alternative.