Rated 4 out of 5 stars

Works for me on FF15. I personally think I like StumbleUpon better back about 4-years ago, when they had user forums devoted to stumble-topics, and when they had green&blue icons. Other things have slid as well, or I would have given it a 5-star, but it IS still one of my favorite addons, and I'm not sure of a very successful product of a similar nature.

This review is for a previous version of the add-on (4.14).