Focus on them: In five years, you should have made a significant impact to the company’s bottom line. Think about how you can achieve this in the role you are interviewing for. In technology careers, advancing your skills is important, too. You should be able to share what areas you want to strengthen in the near term (but be careful that they are not areas of expertise that the company needs now).
Any candidate can read and regurgitate the company’s “About” page. So, when interviewers ask this, they aren't necessarily trying to gauge whether you understand the mission—they want to know whether you care about it. Start with one line that shows you understand the company's goals, using a couple key words and phrases from the website, but then go on to make it personal. Say, “I’m personally drawn to this mission because…” or “I really believe in this approach because…” and share a personal example or two.