it's basically where you're having more than one conversation in one thread at the same time, and replying to everything that the other person put in their post
Person one's post, intending it to be one stream of speech:
"Hello!" They said. Blah blah.
"Do you think it's cold today?" Blah blah.
"I think it's cold. How do you stand it?"
Person two's post, replying to every single statement made:
"Hi!" Blah blah.
"I don't think it's cold today. I wore a sweater so I am adequately prepared." Blah blah.
"The sweater helps! And I think I'm just naturally warm blooded. I was raised in the extreme north, so it's very cool and fun." Blah blah.
Person one's post, now also having to reply to every single statement made, and as a result the thread is now one paragraph longer than it was:
"How are you?"
"A sweater... God, that's smart. I am not warm blooded I am very cold blooded."
"I Should have worn a sweater, but I didn't because I am a weak baby. I think sweaters are vastly inferior to dresses."
"Oh, cool! The north? Whereabouts? I'm more mid...range, or whatever, myself."
basically it's just... when everybody tries to respond to everything that the other person writes, when that's... just... it's just not feasible, in my opinion, since conversations just do not go like that. and then the threads just get longer and longer and after a while you don't know what you're even responding to at some point and it's like... please... let me rest. i like to have my character focus on whatever is most interesting to them and reply to only that part (though that doesn't mean that they don't hear it. it's just that not everything is reply-worthy, you know)