If you have hundreds of bookmarks in different folders like I do you may add bookmarks to your system that you have already added to it previously. Firefox bookmarks are not managed easily despite its bookmarks manager, and the core reason for that is that you cannot display them all at once when you are using folders.
But even if you could do so, you would end up with a very long list that you would have to go through manually to check for dupes. With manual checks out of the question, it is add-ons or third party tools that we need to use to manage our collection of saved bookmarks.
The Firefox extension Bookmark Duplicate Detector is helpful for users with a lot of bookmarks. It can aid you when you need to import bookmarks from another system to prevent that duplicate entries are added to your bookmark list.
It also allows you to search for duplicates in your bookmarks to delete them afterwards. The best feature as far as I can tell is a warning whenever you want to add a site that is already listed in your bookmarks. It displays the location of the old bookmark and prompts you for action. Possible actions are to add the new bookmark as a duplicate entry or cancel the process.
Other features include options to backup your bookmarks and a search feature that lets you search your bookmarks for names, description or keywords. This can be useful if you have a large number of bookmarks.
Update: The duplicate bookmark extension has not been updated since 2009, and is therefore not compatible with all versions of Firefox from version 4.0 on. There does not seem to be a comparable extension available at the moment to check the bookmarks for duplicates from within the browser.
Windows users can make use of AM-Deadlink instead, which can check for duplicate and dead bookmarks.
Bookmarks Checker is a new add-on for Firefox that is fully compatible with all recent versions of the web browser. It checks the bookmarks for dead and broken links only but that is still really useful in my opinion.
Bookmark Deduplicator on the other hand scans your bookmarks for duplicates and offers to remove those that it finds. You need to open the Firefox Add-ons Manager, click on options next to the add-on and there on the start button to start the search for dupes.
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Ghacks is a technology news blog that was founded in 2005 by Martin Brinkmann. It has since then become one of the most popular tech news sites on the Internet with five authors and regular contributions from freelance writers.