How about creating hundreds of millions of certificates, developing a new standard protocol to interoperate with CAs, managing millions of registered users, man

How about creating hundreds of millions of certificates, developing a new standard protocol to interoperate with CAs, managing millions of registered users, managing certificate revocation, logging to certificate transparency logs, running OSCP responders, developing clients for a wide variety of platforms, and keeping up with the latest happenings in the crypto world?