Excellent extension - I've had many bookmarks for 10+ years or older. Extension quickly identified the ones no longer working - duplicates and redirects. My initial bookmark count was 2119 now 769. No problems whatsoever with the extension
So ein tolles Helferlein! Da mußte ich doch mal gleich die Spende anklicken. In der Hoffnung, daß Bookmarks Organizer bald von Mozilla als "Empfohlen" qualifiziert wird. Und vor allem eine Art Whitelist updaten!
The function of this Add-On is difficult to automate because testing all those sites mechanically is going to set off countermeasures. Plus, where cookies have been deleted, the client is going to recognize gateway portals as a failure to load.
I give it 5 stars, but I do recommend that you implement check boxes for batch whitelisting because you're always going to get a lot of false positives.
EDIT: I just noticed the filter boxes at the top of the tree. You might still simplify whitelisting, or allow filtering entries as you go. Still, no redundancies or procedural anomalies. 5/5