The thing is, the topics and posts themselves don’t automatically get involved with these Privacy laws, until there is PII (Personally Identifiable Information) Inside them. In most circumstances anonymization is enough. But Although I am not a lawyer, part of my work gives me full access to freely speak with lawyers particularly in 2 respects. Cybersecurity and Copyright Law. So for those 2 topics, I can confidently speak for not all countries but generally how these laws work in most cases.
As soon as a post contains a link to another place, if that place is another platform owned by someone else, then that can be considered PII, because even after anonymization someone can follow that link and find who originally created that post.
We basically already do on the permissions front, but not the licensing, we can, though that won’t really matter in the end, I’ll explain.
In case you don’t care
TL;DR: Most places by default already award you the copyright and licensing rights to protect your creations as is. Regardless where you go, and regardless your agreements to others. but you should still read your local copyright laws as they can differ in the details.
Disclaimer, everything I’m about to say could be wrong, but I speak with lawyers about this often and I know enough that the general gist of what im saying is true.
Protecting Copyrights
Copyright law is not what most people think it is. Most people think that all the countries in agreeance on what copyright is and how it’s used follow the DMCA. This is not how copyright works.
From a legal perspective copyright does not exist until it is made to exist. This is done by either your local countries laws or by your person defining the licensing and how you execute that licensing to any given country.
For ex. If I create a movie and I live in a country where we have no copyright laws. I cannot legally protect my creation from piracy inside my country, but if I sell it in the US, then all US citizens must abide by my licensing and the DMCA.
If I make a movie in the US, and sell it abroad, whether I can protect my movie from piracy entirely depends on that local countries laws and whether they will extradite someone or practice the DMCA. This is why you can find online hosts that will ignore DMCA notices. It’s important to know this USUALLY means they will also ignore other copyright notices such as the EUCD (European Union - Copyright Directive), Bill C-11 (Canada - Copyright Act), Australia - Copyright Act 1968, UK CDAP, etc. but they might NOT ignore these notices.
A lot of countries abide by opensource licensing like the various copyleft style agreements and EULA, and other licensing agreements you’ve probably seen in your lifetime. It is also important to know the difference between a license and a copyright.
Copyright vs License
A copyright is any idea that is defined that you own.
A license is access thereof to that idea by which you might not own.
(Ideas being creations of your mental faculties, books, music, movies, etc.)
How most places handle Copyright and Licensing
In most jurisdictions once a person has made a creation, they by default have an unequivical ownship of that creations copyright. By default there is no license involved and it needs to be made. However a property of a license is it can be revoked essentially at will because it was not made to begin with. Once a license has been made, it can be changed, but the members to which have that license need to agree to the new terms.
Again this is not always the case, but is in most jurisdictions where copyright and licensing exist
Nor, do I offer any real help. 
FML, usually do ‘puny’ stuff like this myself! I’ve always subconciously thought that your Profile-Pic was a bit, unfitting.
Time to script something.