An unnamed TealPoint employee recently posted the following explanation about the US trademark law to the palm-entrepreneurs mailing list. As it is excellently written, I felt like reposting it here - enjoy:
1) Functionality
A term cannot usually be trademarked if it is purely descriptive of its functionality. For instance, you cannot trademark “mileage log” for an app that tracks mileage, but I don’t think “Trip” is considered generic by this definition because the name doesn’t describe exactly what it does (trip planner? assistant for clumsy people? Grateful Dead tribute?). Instead, it is considered a “suggestive” mark which can indeed be trademarked. Being a common word isn’t a problem as long as it isn’t “functional”, as “Apple”, “Flash” and many other words are trademarked in a specific application.2) Incontestability
After five years, a registered term does not automatically become “incontestable”, but only if an “affidavit of incontestability” is filed with the PTO. Even then, the term can still technically be contested, but the term cannot be ruled invalid due to “prior art”, “functionality” or “lack of distinctiveness”.3) Infringment
Even if it’s incontestable, just including the term as part of a competing product’s name is not automatically infringement, especially when only a limited number of words could apply to an app that tracks automobile mileage. Otherwise, people would just trademark all applicable words (”mileage”, “log”, and “trip”) and nobody would be able to name a competing product anything at all. The intent of trademark law is to prevent confusion, not limit competition.When determining potential trademark infringment, the PTO assesses the “likelihood of confusion” on the part of customers, e.g. whether they might purchase one product believing it to be the other. If Steven’s product were called “Trip Deluxe”, or even “iTrip” then I think there would be a fair case for infringement. I think it unlikely, however that someone would think “TripLog” and “Trip” were actually the same product.
