Blocking bad sites and annoyances
From MozillaZine Knowledge Base
This article describes blocking unwanted sites and annoyances within sites.
Adblock Plus extension
Suppose you find a site particularly annoying
You can block the site yourself with the "Adblock Plus" (ADP) extension with your own filters for instance:
Neither site is blocked by the subscription filters "EasyList USA" nor "Fanboy's List". Adblock Plus will do nothing without filters and a subscription or two is easily added after installing ADP. The extension is large but well worth having on your main or only Firefox profile.
A nice feature of Adblock Plus filters is that each subscription, and your own additions are maintained separately. Another is that you can bring up a "blockable items" report to see what can be blocked as well as what is blocked, and you can see the specific filter that is blocking an item as well as the source or subscription group. Suggest sorting on the "State" column so blocked items appear at the top. You can change options, disable/re-enable from the toolbar ADP icon.
Adblock Plus - Open blockable items list ("Ctrl+Shift+V") or from right click on icon, shows all the urls on a page and if blocked by a filter shows the filter. All of the preferences and subscription filters are available from Preferences... ("Ctrl+Shift+F").
BlockSite 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. Uses wildcard (*) so you can block variations of a site.
You can use an extension such as "WOT" (Web of Trust) to warn you of a bad site, it is based on user experience and often just what people seem to think a site is about based on the name, the ratings are inconsistent. The extension will block access to sites deemed bad, but you can override the warning.
"McAfee Site SiteAdvisor" system is better it is based on analysis of site tracking with virtual machines, every link to see what happens. Both WOT and SiteAdvisor extensions place warning symbols on Google search results, but SiteAdvisor is not working well with Firefox, and their extension is not on addons.mozilla.com so the code is not subject to review by Mozilla. You can however get a site report
Get a site report for a specified site
A keyword shortcut is a bookmark with a keyword and may include substitution.
Name: site: SiteAdvisor Lookup (Web Safety Ratings)
You might use two keyword bookmarks as above one as "site:" the other as "siteadvisor", and create a similar bookmark for WOT as "wot:".
Firefox builtin protection
Firefox has a reporting system for reporting Web Forgeries (Phishing) under the HELP menu.
Tools > Options > Privacy
Having a good hosts file on your system can protect your entire system cross-application and all browsers and all your Firefox profiles against a lot of malware sites or extreme annoyances within sites frequented by a lot of people. See Blocking Unwanted Parasites with a Hosts File.
More information: on extensions and items mentioned in this article