Several users reported that the latest upgrade of InvisibleHand for Firefox to version 2.0 has caused many websites to log out without a reason. This is due to a bug that we didn’t catch during testing. I am very sorry this has happened. I will make sure the next release of InvisibleHand for Firefox performs well.
If you are affected by this problem, please either downgrade to 1.8.2 (which is up on the Mozilla addons website right now) or upgrade to 2.1 when it is released (should happen today or tomorrow).
Again, I’m sorry this has happened and I’ll make changes to the development and testing process to make sure the bugs like that get caught early.