A trademark is a mark you use in order to identify your good or service.
For instance, IPfever is a trademark as it’s associated with services and contents offered at IPfever.com. If a law professor wants to start a blog about IP, she shouldn’t name it IPfever. Such naming would mislead people to think that the blog was associated with IPfever.
But, on the other hand, if a medical researcher encounters a feverish symptom related to Information Profession, she’s free to call it “IP fever,” to publish a paper titled “IP fever,” and so on. There’s no problem with such designation because the trademark IPfever, at the moment, has nothing to do with medical diagnosis.
So, you can freely catch an IPfever, and you may sell an IPfever brand roasted coffees. But you may not provide an IPfever service if that’s related to what is offered on ipfever.com.