> The name “Audacity” is a registered trademark.
It's a regular trademark - it's been acquired.
The trademark isn't covered by the GPL.
Jason Rohrer ran into this very issue when other developers made their own client for his game, using a variation on the game's name. They didn't respond to him asking that they don't use the name, and eventually he was convinced that trademarking the name is the right tool to project it. The original game client is still open-source (and maybe the server too, dunno).
So if for example I wanted to cross-promote my other products or add a "pro" paid version of some sort, I could do that, and those would end up in the main version most people are downloading.