https://xenforo.com/community/resources/aayush-hide-hack-v1.1618/ It's an addon that allows people to create hidden content that only people who meet certain qualifications can see, however the main qualification that can make this useful is forum ranks. This will allow people to include proof in a forum report(or appeal) that includes sensitive information(such as porn/disturbing spray, map exploits, etc), while only allowing staff members to see that content. For example, if I see someone with a disturbing spray, I can include a SS of the spray in the report, however only staff can see it. Non-staff will see something like this: while staff will see something like this: This also includes permissions for the whole thing.
Hmm, any other functions it can do? I mean, what you are speaking of seems to be a good deal but I can't really see it being applied to much else.
Another one of the "qualifications" you can set to see the content is to like the post, people could use that for giveaways. The instructions for the giveaway can be inside the hidden content, or maybe what they're giving away is inside of it.
Or if someone is making a report and they don't want the video url going everywhere, they can use it to hide the video to only staff (and maybe the reported party if there elicits a response from them)