There's no reason a blog has to be serious. But if you want to be taken seriously, act seriously. This doesn't mean you can't be funny, or consciously vapid, or light-hearted, or antagonistic, or anything else a blogger might want to be. But authority is not handed out at request. For example, the right to be contrary and not be judged as merely reactionary is earned through effort and experience, not by the act of being contrary.