No, he didn't compare Zuckerberg to a rat. "Smelling a rat" is an idiomatic expression [1] that means that something is suspicious or wrong. [1] http://idioms

No, he didn't compare Zuckerberg to a rat. "Smelling a rat" is an idiomatic expression [1] that means that something is suspicious or wrong. [1] http://idioms.thefreedictionary.com/smell+a+rat http://idioms.thefreedictionary.com/smell+a+rat