As this Feverbee blog reminds us, public communities attract a lot of new traffic via SEO. As a result, new users are more likely to come in through the back or side door, rather than the front door.
We would love to be able to customize which Topic Sidebar widgets show based on user role.
Use case: unregistered / logged-out users could see an HTML widget with a CTA to join or login, then hiding that widget for logged-in registered users.
Many other use cases could come from there if this was possible.