Do you love your job? Are you excited by the prospect of a new challenge? Are you energized by problems that you encounter in your daily work? If you aren't, this may be a signal that you are in the wrong profession, the wrong position, or have the wrong boss. Think about what you would rather do, and then seek out a career that aligns more closely with your interests.
You will find that the best engineers have all been extremely passionate and energized by their work. If you want to do your best work, you need to be sure that your career is aligned with your interests and passion.
Do you contribute to developer forums?
There are a couple of reasons to ask about open source and developer forum contributions.
If you contribute to open source or have hobby development projects, you most likely exhibit the following traits. You love coding (you will code for free), you are motivated by the challenge of solving a problem, and you are ambitious (what's not ambitious about providing solutions for people you've never met, when you could be watching TV instead). Engineers who love to code are almost always better engineers than those that don't.
If you are a significant contributor to open source projects, you likely know other engineers who contribute to open source. That is important for managers looking to add engineers to their team. They would rather ask their current team members for referrals than posting another ad to any number of job boards.
If you don't have any hobby projects and you don't contribute to open source, be prepared to present alternative information. You are trying to convince the interviewer that you are motivated and interested by your career choice. You could talk about conferences that you've attended, and what you've learned. Make sure you mention any self-study exercises or proof-of-concept demos that you've completed to learn about new technologies.