Even if you say any names if they can figure who you are talking about it’s rechilus. Even if you are just conversing, masiach lifi tumo, and you tell over a story about what some did or said about the person you are talking to which was hurtful in the past and they might have gotten over it but by reminding them if what happened innocently without any names but they remember the incident and who did it and it stoked the coals and delights the flame of anger from the fight they had had, that’s rechilus. There is also no difference whether it’s written or oral, or whether it’s about a person or his business, bottom line anything you say that some did or said which will stir up hatred in the listener’s heart is considered rechilus.