It no worky. It used to work, I was able to synchronize my Chrome and Firefox bookmarks. It still works on Chrome, but the Firefox extension keeps telling me I need to login in, but when I click the login in button it tells me I'm already logged in. I sent a message to their support teams weeks ago and have received *zero* response to date. I'm so glad I didn't pay for their premium service, at this point it's pure garbageware.