Session Time Out
At Stir, we're serious about security, so we include a "session time-out" feature that automatically signs you out if you've been on the same screen for more than 45 minutes.
This ensures that if you sign in and later get up and walk away from your computer another person won't be able to sit down and access your account. This requires a level of caution, though, when you're filling in your profile text or typing a message on the site because a session time-out could result in your hard work being lost.