My website has:<p>- Shopping cart for selling our software and support products.<p>- Forums for discussing our software. Email notifications are available for users who want to follow threads.<p>- Ticket tracker for reporting bugs and making support requests about our software. Email notifications are, once again, available for users to follow threads.<p>- License manager, so that people who have bought our software can get the keys to download the software.<p>How would you suggest we accomplish those tasks without having a sign-in, at all?