you can change the text to whatever you want in your sp theme…  And yes, there were no topics found that you have permission to view…  but of course, that also reveals info that there is private data you are not letting the user see… so our default text follows a similar pattern to opt in – we are not going to reveal anything that might be ‘secret’ and leave it to you…

BUT I really think what you want here is one of the sneak peek features and permissions…  There are permissions for allowing users to optionally see the forum list but not the topics or posts, or see the forum and topics lists, but not the posts…  And if they do try to view a topic or post (by clicking on link that you let them have sneak peek at) you can redirect them to a page where you display a message such as asking them to sign up…

Where do I change the text?

How do I set up the 2nd option of allowing them to view lists of forums and topics and then redirect them to the registration page?

I changed permissions to allow ‘No Access’ guests to view forums and topics. How/where do I set up the rest of the feature by linking them to a registration page?

you have to give them the permission…  first, remove the view forum permission… and then add in the one that you want, can view forum and topic lists or can view forum lists…

you can set the sneak peek message on forum – components – login and registration (though its moving to more appropriate location in next version)…