I'm currently working on a web application where the user can enter some data. Unless the user is logged in, the data will only be stored in localStorage (i.e. in his browser).
I will support syncing that data to the server, but that obviously requires the user to authenticate in some way.
How do I inform the user that the data he entered might not be long-lived unless he logs in/registers?
I do not want to force the user to log in, just to test the webapp (and there's no technical reason to do this). I want them to try it, see if they like it so far and then make the decision if they want to log in/register.
This is similar to this question: How to inform user that settings are in localstorage, and apply to this browser only?