Originally Posted by AdultKing

All domains are ultimately controlled by ICANN.

However trademarks are controlled by jurisdictions, usually countries. A trademark registered in Australia may not be necessarily enforceable in Columbia unless also registered there, as an example.

If company A has a trademark of Wow Widgets in Australia and company B has a trademark of Wow Widgets in Columbia and company B register wowwidgets.com then Company A can't do anything about it.

Even more confusing is that common law trademarks are recognised as well, so an unregistered common law trademark may override a registered trademark in another country simply because of the reach of the common law trademark.

Let's say Pornhub, as big as it is now, did not have a registered trademark but relied on a common law trademark, they could successfully oppose a trademark registration in another country simply on the basis that they are known world wide for their mark.

This is why specialty trademark lawyers exist, it's all very very complex.