Don't need to worry about logins. Nothing is stored here. Best thing to do is to create a custom URL that will always bring the same lists.

i.e. When I setup my personalized options, I have:

http://www.skimhn.com/djWH3hS5

That way you don't have to operate with logins and everyone's setup is share-able. (Then you can look in the future of letting the creator define the url.)