Quirky and a smidge non-intuitive, but this add-on is incredible. The functionality of this add-on combined with OneTab makes Firefox insanely useful for the poweruser. More people need to know about this add-on.

What do I do with it? I have my Gmail accounts each open in their own protected named island. All of my google-verses live separately: day job, my two small businesses, an association I volunteer for, and personal. Beyond Google, I have 10+ other containers for Development work, Writing, Finances, anything Government and tax related, Shopping, Social Media, etc. And none of them can talk to each other.

This add-on is awesome. And with OneTab I can change context for what I am working on at any given moment, snapping in and out of whole suites of tabs.

This is powerful stuff.