Comments by "Anony Mousse" (@anon_y_mousse) on "Nokia Forced This FOSS Project To Change It's Name" video.

From a legal standpoint, if the other company produces a different category of product they can't enforce a trademark on the name. So another company that produces say farm equipment could call themselves Nokia, but manufacturing phones, a big no go. I'm less sure about an instance where you don't actually sell a product, but that's not been tested in the courts that I'm aware of. Microsoft had a similar issue with wxWindows way back in the day and now it's known as wxWidgets instead. If it were my project I would've fought it since the name and goal of the project was different enough from the OS, but I'm a bit nuts.
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