I'm wondering what I would do to go about letting a guest use my web application without registering, then if they attempt to save their work they are prompted with a registration. This will be in a rails application by the way. Can I just allow public access to part of the work flow, then when they save check if they're a registered user (by session value, or cookie?). If they aren't a registered user, save all their work into the session and let them fill out a sign out form. On successful registration automatically log them in and initiate the create on the db?