I didn't get the job because I think I messed up in question b. I could only think of one way Facebook generates revenue (advertising), I forgot about the cutesy hearts and stuff you can buy as another source of revenue. But I couldn't figure out how to come up with how much they make per year accept rambled on how much each customer would pay and depended on number of page impressions, size, format and frequency of add displayed and to get the total...I mentioned that I know how much reported net worth of Owner of FB is so it has to be x much more to cover cost of IT, resource, etc.