I think you can look at this another way too. How many people in other industries voluntarily embark on pet projects or hobbyist experiments that involve the sa

I think you can look at this another way too. How many people in other industries voluntarily embark on pet projects or hobbyist experiments that involve the same things they do at work? How many people in other industries blog about their profession in their own time? And not just about their day to day, but about new things they've found or interesting things they've figured out. People want to go home and leave work at the office, but it's not at all uncommon for a programmer or developer to carry on in their spare time, working on their own stuff. You probably started off your career as a hobby in the first place. Sometimes it can be hard to switch off when plenty of other people manage it fine. It seems almost implausible to imagine a fellow colleague who wasn't interested. I also think that specialist journalism is another profession that almost expects 'extra-curricular' interest in the field.