[nerdponx]

Sort of. The USA you can claim trademark rights without a registered trademark; that's the difference between ™ and ®.

But the law follows "use it or lose it" rules. If you don't defend your trademark, then in the eyes of the court it is no longer a trademark.

[pferde]

Hold on, that's "defend it or lose it". Author of libcurl clearly is using the name, there are new releases coming out quite often.

[nerdponx]

My wording was unclear, yes. If you aren't defending it, you aren't using it as a trademark.

Think of the term literally; if it's not exclusive to you, it's not longer a "mark" of your specific "trade". It's just a "mark".

[pferde]

Fair enough.