Rated 5 out of 5 stars

Excellent! Easy to use, easy to customize, great free basic use, has tags, searchable from my devices, computers; toolbar can be toggled between full toolbar to a single icon. The most used extension on my Firefox & also Google Chrome. I highly recommend Diigo.

This review is for a previous version of the add-on (5.1.0.33).  This user has a previous review of this add-on.