I was contacted to interview for a position with Bloomberg in a technical role. First spoke with a recruiter, than a manager and then a more senior manager. At each step, I was professional as were they. But after the final interview I sent off an email thanking them for their time and that I looked forward to hearing from them. Then not so much as the courtesy of a reply saying "We'll let you know" or "Thanks for all the effort" and no word on how the position was filled. When I interview, we always thank the candidate and let them know we went with another interviewee. The overall interview process took an aggregate of 4-6 hours of my time and they couldn't take 5 minutes for a simple email. Maybe just an oversight but a pretty unprofessional one at that.