I think it can't hurt. I work in a more conservative industry and I sent thank-you emails the day after an interview (I got hired, obviously not only because of

I think it can't hurt. I work in a more conservative industry and I sent thank-you emails the day after an interview (I got hired, obviously not only because of the follow up). I would avoid physical mail because it will take too long to reach the recipient and I would keep it short (2 or 3 sentences). If everyone does it, you'll only stand out by not doing it and in a bad way. If no one does it, you have the possibility of appearing more professional.