According to the source, on Sunday morning more than 20.3 million concurrent users were registered on Steam. This is a new service record. There were 6.2 million people in any game at that moment.
The source explains the record figure by the fact that many people now remain at home because of the coronavirus. The fact that many users enter the service but do not play is partly due to the fact that they use other functions of the platform, but in most cases this comes from -because Steam is logged in by default at system startup.