How to block Facebook and Twitter using hosts file

Edit the file \windows\system32\drivers\etc\hosts and add following lines at the end of the file:

Facebook

127.0.0.1 login.facebook.com
127.0.0.1 www.facebook.com
127.0.0.1 blog.facebook.com
127.0.0.1 apps.facebook.com
127.0.0.1 en-gb.facebook.com

Twitter

127.0.0.1 www.twitter.com
127.0.0.1 twitter.com