The Login/Logout tab doesn't have consistent behaviour. The login tab behaves kind of like a tab, new content is displayed and nothing happen other than loading content. Once logged out the tab really becomes a button. Clicking the tab invokes direct action. The tabs for login/logout don't follow many of conventions found elsewhere.

* The logout function uses a get request for it's action. This can cause problem with tools like the Google Web Accelerator. For more info: http://37signals.com/svn/archives2/google_web_accelerator_hey_not_so_fast_an_alert_for_web_app_designers.php