What is the difference between dayo and desu? I was participating in a chat and a person said genki dayo. I am assuming that dayo and desu mean the same thing and can be used interchangeably. Thank you.
7
です is polite form. だよ is casual and friendly. You shouldn't use them interchangeably.
If you use だよ to your boss or unfamiliar people, they would think you are rude.