Now a day’s WWW world fields with millions websites. By some of them you may addicted, some are seriously important to you or some are totally useless to you. Now I am talking about those useless sites. If you want to block those unwanted website in Mozilla Firefox then go for a free Blocksite add-on. It is a simplest way to block some websites of your choice in Mozilla Firefox. It will disable all hyperlinks to these websites. It also provides a password protected feature that helps to block unwanted changes by strangers.