This is really good addon but it slows down Firefox significantly. I had to test all my addons one by one to figure it out. Its a shame as the Chrome counterpart is fast. My usecase is heavy browsing (loads of tabs). It might be ok for light usage.

Works fine, but could have more integrated features such as category change when browsing pages, directly from the extension itself.

As others have mentioned, it needs cookies permissions:
https://help.rescuetime.com/article/90-the-rescuetime-firefox-add-on-does-not-work-with-my-custom-privacy-cookie-settings-in-firefox

Doesn't work with firefox developer edition. RescueTime shows everything under "firefox developer edition" activity without displaying visited websites.

Tested with firefox developer edition 64.0b6 and latest RescueTime 2.10.1.1355 under Ubuntu Linux 16.04 LTS

Worked like a charm!

It helps you be productive

doesn't work

Simply does not work. Very disappointing for paying members.

Still doesn't work on Firefox Developer Edition. The *title/name* of the page is shown individually, but the *site address* isn't actually identified! All my activities are lumped together under "Firefox Developer Edition". The customer support has also been totally unhelpful on solving the issue.

Strangely it does work on Firefox.

Update Dec 2018: The bug still isn't fixed after 7 months, which is pretty bad.

Don´t use this addon, mines your data as you can read in it´s policy.

Excelente aplicacion que me ayuda a ser conciente en ue uso mi tiempo