As you have probably noticed, we have recently implemented a timeout on login sessions. This means you will be automatically logged out of the site after one hour of inactivity.

This is a basic security measure to prevent other people from impersonating you on a publicly accessible computer. At some point we may add a "remember me" option so that you can remain logged in indefinitely from computers that you trust, but as usual, there is a trade-off between security and convenience.