Being well-versed in your own personal skill set isn't enough. If you walk in ready to spew flattering facts and charming anecdotes about yourself but have no apparent background knowledge of the company you're hoping to join, you've seriously handicapped yourself right out of the gate.
Interviewers want to know that you care enough to learn about the company in advance. An encyclopedic knowledge of your own accomplishments shows that you think you can be an asset to someone. When you make it clear that you researched the company prior to your interview and still decided to move forward with the process, it shows that you think you can be an asset to that company in particular.
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"So clearly I'd fit in with what you do in ... uh ... businessing?"
Rest assured, other candidates have taken the time to study up. You should do the same if you want to remain competitive.
Tip: Don't just study up on the company. If possible, learn a thing or two about the person (or people) you'll be interviewing with. Even if you keep the results of that research to yourself, familiarizing yourself with the interviewers means you'll be more comfortable when talking to them. Calm and easy to talk to wins over nervous and uncomfortable almost every time.