Well, YC has had 'tart' trademarked since 1991, so I don't think any of us can complain about not being able to use it. Like it or not, this is the purpose of trademarking. Back then, it was probably a novel term (in this application ayway) and they wanted to protect it. Tart has become a sort of generic term but that doesn't mean everyone should have the right to use it. I'm sure E's letter is genuine, and they will follow up on it. I personally think it's bad advice to 'ignore' a C&D from a company like YC. The bear situation, although a certified patent, IMO is a different situation....there seems to be a genuine question as to the validity of the idea and who should have received a patent, if anyone, but unfortunately someone will have to fork out some big $$ to fight that one. I don' think there's any question about the 'tart' trademark. You can't tell me that if you (meaning anyone here) came up with a novel term for something you produce and gain a trademark, and 10 years from now when that product is common place (and you're rich, heh heh) that you wouldn't try and protect that trademark. JMO.