As thought experiment, imagine that inbox.google.com stops working (oh, wait, it will…😭). Theoretically users could pick up the phone, call google, identify themselves and ask a google employee: please tell me, what messages do you have waiting for me? This mental exercise is a great way to figure out what your business is about. If a customer walked by your office, what questions would they ask? What pieces of information would you try to save if the office is about to burn down? What user interactions ultimately generate money of your business?