CompuServe was an American online service, the first major commercial one in the world. It opened in 1969 as a timesharing and remote access service marketed to corporations. After a successful 1979 venture selling otherwise under-utilized after-hours time to Radio Shack customers, the system was opened to the public, roughly the same time as The Source. H&R Block bought the company in 1980 and began to more aggressively advertise the service.

In computing, time-sharing is the sharing of a computing resource among many tasks or users. It enables multi-tasking by a single user or enables multiple-user sessions.