It actually does what it says, and what's needed. Unlike many other extensions like this, it works to combine trees of folders properly, and then to identify and remove all the duplicate bookmarks in each individual folder.
The addition of an excluded folders is a major bonus when dealing with external bookmark sync tools.

ok, now is working good without crash

Thank you for your hard work. But sometimes it'd be useful to have duplicates. So could you pls add a function to allow that? By that I mean allowing adding the same url in different folders at the same time. Now it is impossible. Best wishes!

Merging duplicate folder is really great feature!

Looks good, but please add a function to include only certain folders in the duplicates search. If we have 100 folders and only want to compare 2, it takes a long time to exclude the other 98.

Problem solved.
All 'find' functions are fast, very fast.
Wishes:
1) A progress bar in the merge duplicate folders
2) A "Select all" option in the duplicate files result (active on ony ONE duplicate list)

Five stars even as it is.

I am a Chinese user, thanks to the extension provided by the author, from chrome to firefox..

This add-on works very well in all of its functions. The "Merge duplicate folders" feature is unique and this is the only add-on that I have found to get rid of multiple duplicate paths. It would be beneficial to have a way to see the progress during the "Merge duplicate folders" operation so that it can be seen when the operation is complete.

Fantastic tool very well done.
Just one small cosmetic suggestion, after the scan the list and addon title are not centered on screen.
See these image for better understand:
Before: http://oi64.tinypic.com/m82nep.jpg
After: http://oi67.tinypic.com/nfjpth.jpg