Meta Project Manager interview questions

Execution Question; You are PM for Group buying /Selling on Facebook. (Apparently, this is a feature ). What metric would you select to see how well the feature is doing? Follow on questions: What are the downsides of using this metric? How would you mitigate the downsides? What if an engineer came with an idea to place a feature on the facebook homepage that would show items that you may be interested, would you implement this? What if you ran a test to test the feature (the widget on fb homepage) and the results came up negative, what could be the cause of this?