Block websites with /etc/hosts

What's /etc/hosts for?
Every UNIX-like OS has a file for resolving hostnames to IP. You can block specific hostnames by directing them to your localhost IP, which is 127.0.0.1. Usually i block a few sites i visit regulary, which are distracting me to study. In following an example is listed.

# Address       Hostname
127.0.0.1       localhost
127.0.0.1       localhost.localdomain
255.255.255.255 broadcasthost
::1             localhost
127.0.0.1       local

127.0.0.1       9gag.com
127.0.0.1       facebook.com
127.0.0.1       facebook.de

The first line, beginning with the hashtag is a comment.

What about windows?
In windows 7 there was a similar file under C:\\system32\drivers\etc\hosts. There should be a similar file, in newer Microsoft operating systems. http://bfy.tw/1Vce