Use 'what does... know?' to inquire politely about someone's knowledge on specific subjects.

Inquiry Context

Use the phrase to clarify someone's expertise or familiarity with a topic before seeking advice or opinions.

Clarifying Expertise

Be aware that questioning someone's knowledge can be sensitive, so pose the question respectfully.

Be cautious as 'what does... know?' can sound dismissive and undermine the person's credibility.

The phrase is often used informally among friends or in casual conversation to express skepticism.

Sometimes it's not a real question, but a way to express that someone likely knows very little.