I see videos and images from Twitter feeds, and they are full of stuff without copyright notices.
This is just one small example, I see thousands of posts all with sound, or video or images taken from somewhere else.
Sometimes these posts can be used to make money, however indirectly, such as increasing your following, which you can then serve ads to on your website or through YouTube ads, etc..
Youtube doesn't allow you to upload a direct song of a famous artist, and there are other copyright infringement blocking attempts made by Twitter and other platforms when you try and upload something.
But in general, what is the law here, is social media basically one big loophole in the law where you are allowed to use copyrighted material? Why couldn't you do the same thing but put your "posts" on your own website with ads? I don't see the difference. Hoping to understand why millions of people are allowed to essentially copyright infringe using social media, yet you aren't allowed to put the same images/sounds/videos on your own blog or website.