that sounds like an interesting concept, similair to part of what something I am working would like to acheive. Are you providing a structure or allowing 'interviews' to be whatever form/structure the interviewer wants? good luck, its a problem i havent seen solved properly yet!

We're providing a structure: Founders enter open-ended questions and reference links. Interviewees answer questions while referring to the company website in an iframe above.

So you can assign tasks then ask usability questions, or gear the interview more generally toward your business concept, how well users understand your site's value prop, etc. Love to hear more about wht you're working on!