The best add-ons for children and for parental control
BlockSite is an extension, which automagically blocks websites of your choice. Additionally, this extension will disable all hyperlinks to these websites, by just displaying the link text without the clicking functionality.
Block web pages containing pornography or any other type of material based on keyword lists.
LinkExtend provides meta-site-ratings for computer safety, child safety, company ethics, and popularity. Safety results come from eight online services giving you a safer browsing experience. Site links, titles, files and reviews are also included.