One fairly common “law of web/mobile physics” is the ratio of registered users/downloads to monthly actives, daily actives, and max concurrent users (for services that have a real time component to them). I call this ratio 30/10/10 and so many services that we see exhibit it within a few percentage points here and there. Here’s how it works: 30% of the registered users or number of downloads (if its a mobile app) will use the service each month 10% of the registered users or number of downloads (if its a mobile app) will use the service each day the max number of concurrent users of a real-time service will be 10% of the number of daily users We see these ratios across social web apps, social mobile apps, games, music services, and many other consumer web and mobile services.
— 30/10/10