I am storing some user settings for a SharePoint site in a list. I want to persist these while the user is in an active session, but remove them when they come back. If this was asp, I would simply store the session id and compare it to the current session id. I don't necessarily need a session id, just a way to determine if they are a return visitor. I don't want to have to enable session state if this will slow down the app. How should I handle this?