What does this mean? Does it mean you need to zap in order to leave a message? So it means there would be two reply tabs? one tab full of replies that anyone can reply and the other tab full of replies that required a zap?

That would solve the spam problem. I've always said that eventually every reply should require a Satoshi or a fraction of a Satoshi. This system would destroy spammers, scammers bots freeloaders.