People's preliminary thoughts can then be quoted against them as if they had been fully considered. Hence one needs to make sure the other person is aware of the informal nature of the conversation. In other words, that the other person knows the conversation is not to be recorded and that the information is to be regarded as confidential until the matter has been fully considered. There are, however, many formal oral communications, such as selection, grievance or appraisal interviews, or when negotiating. Characteristic is that a record is kept by those participating.
Rumours are hearsay.
One person tells the next who tells another, and so on. But there are personal barriers as people tend to keep back, elaborate or enhance information in accordance with their likes and dislikes. Hence information tends to change in emphasis and content as it is passed from person to person. This makes rumours so unreliable a source of information. Be clear about the purpose of the communication.