The user navigates to content that requires registration to view, and a modal box appears over that (blurred) content and offers options to 'register' or 'not'. Should the 'not' option navigate back to the previous page? Why or why not?
- If you want to seal a deal don't block users from viewing content until they have reached "point of purchase" Amazon only asks users to login at checkout!
Login walls require a significant interaction cost: users must remember their credentials (if they have an account) or take the time to create a new account. Therefore, sites should use them only if users will benefit significantly from the presence of these walls.
If you have to (Significant benefit to the user assumed), then, you should indicate clearly to the user via labelling as well as visually that privileged content lies beyond. This will allow them to anticipate whats coming next and adequatly frames the decision process.
In case the user decides to click anyway then show a friendly message with emphasised login/signup options as well as a "No thanks" if they are not interested then they will navigate back.
It would be good to display a brief on-page message over the blurred content that reminds the user they need to be registered. Perhaps with less detail than the modal window.
Better still, it would be good to expose a small portion of the content to give them some incentive to register.
Test the prototype with users, and ask them to close the modal, then ask, 'You've closed the pop-up window. Is what you see now what you would you have expected?'