Rated 5 out of 5 stars

Your idea is indeed very good! I am experimenting with this addon. So far this is my understanding:

Each tab (except the one you're currently) on kind of "hibernates" after the user specifies a "timeout".

Yes indeed, the memory consumption also seems to go down a bit. It is sad that "the memory leak in Firefox" legend still exists:(...

However, kudos to your addon! Only problem is I now open up a lot more tabs:)

This review is for a previous version of the add-on (1.4.2).