Milkey's law of irrelevance
By the time you finish typing a long comment in a chatroom, the subject has changed.
Bob1: my dog is so cool! (John3 is typing) Anne2: Really, what breed is it? Bob1:Jack Russel. Anne2: my aunt has a parrot. Bob1: parrots are so funny. Anne2: Yeah, totally. John3: Cool! I have a dog too! Bob1: Huh? John3: Milkey's law of irrelevance at work. :(.