After applying online to a position in a regional office, I got an email from the hiring manager the same week requesting a half hour phone interview. We had the interview, which was more of a conversation, and he indicated that he was eager to make a hiring decision during the following week and have someone start 2 weeks from that Monday. I thought was odd since the decision would be made after just a single 30 minute phone call and wouldn't even allow for 2 weeks' notice to a current employer. He also said that he was the type of person who would call everyone back regardless of the hiring outcome. I waited until his proposed timeline had come and gone, sent an email to follow up, and never heard another word back. I figured out someone had been hired for the position by searching on LinkedIn. It seems to be more common these days that companies reject candidates by never getting back to them, but when you make it a point to tell people they'll definitely be hearing back from you either way, it's incredibly rude and unprofessional when you fail to deliver.