Addon does not work Rated 1 out of 5 stars

No deletion at all.
(Iceweasel 43.0.2)

Rated 4 out of 5 stars

Great addon, One suggestion though. Please add a confirmation to the Forget this Site and Forget this Domain features, I accidentally erased all my history for one of my sites, when I only meant to delete a few of recently visited pages. Which was like hundreds of visits which I used to keep track of what I had/hadn't read. There's nothing I can do about it now, but it might be useful to have a confirmation say "Are you /sure/ you want to forget about every visit to this site as well as delete your cookies for it?"

Good catch there! Rated 4 out of 5 stars

If you live and work alone this one will be LESS useful. However, the developer did score by spotting a potential issue here. It is a real hassle to go in there and manually delete history and this makes it a whole lot easier.

Highly Recommended for Cleaning Up History Rated 5 out of 5 stars

If you are like me, and like to remove clutter from your browsing history, you will probably like Mass Forget. It is a simple add-on that does exactly what it says it will do. For removing whole domains from your browsing history, it is much easier than having to search for the domain.
If you are a person who doesn't care much about tidying up your browsing history you might not find use for this add-on, but if you are I think you will find this to be an excellent tool.

This review is for a previous version of the add-on (0.6.1-signed.1-signed).