No. I just think it's unethical to make money from someone else's work without compensating them.

"But everyone else is doing it" is the kind of reasoning small children use.

That was not my reasoning, I thought you had some examples in mind.

I think the only solution to respect the copyright for this kind of content (amateur content with no identified author) would be to stop publishing it: you can’t sue Tumblr, Facebook, Twitter etc.

Just to be sure: are we talking about the original authors, or the websites who add their watermarks on it?

Lol, touché! and how about google? does google have permission to show gifs jpegs/whatever video/.. online when people do a search on any term in particular? Guess there are loopholes for big companies only ;)

You either have no money to pay for a lawyer and go bust or you buy all the lawyers so that no-one will be left to sue you... sort of kind of... doesn't make sense but you catch my drift right? :D