Most instances don’t have a specific copyright in their ToS, which is basically how copyright is handled on corporate social media (Meta/X/Reddit owns license rights to whatever you post on their platform when you click “Agree”). I’ve noticed some people including Copyright notices in posts (mostly to prevent AI use). Is this necessary, or is the creator the automatic copyright owner? Does adding the copyright/license information do anything?

Please note if you have legal credentials in your reply. (I’m in the USA, but I’d be interested to hear about other jurisdictions if there are differences)