Too many bookmarks, you need to check for the duplicates and non working bad links... and if you are using Google chrome, then you are take a breath of relieve. Bookmark sentry dashboard extension - "A Chrome bookmark scanner that checks for duplicate and bad links.
This is a simple scanner for your Google Chrome bookmarks. It checks for bad links and duplicates and displays a report if it finds something. It can be scheduled to run a scan every couple of days or not at all. It's kind of like FireFox's "Check Places".
It's made to help you and get out of your way, as such there are no icons in the toolbar.
You can also find them on Facebook