Noun: The act of contributing irrelevant information to a conversation, or the attempt to communicate useless information to a person.
The same as spamming an e-mail adress or forum with useless information, only verbally.
Person A: Have you seen Citizen Kane yet? It's worth the time you know.
Person B: No, I haven't, but guess I'l have to do it sometime.
Person C: Heat can be quite warm sometimes. (Verbal spamming)