Workers are connected to workers in other accounts through a channel mechanism, which is extended in library.worker into the Connection node type.
Connections can be setup manually through the Connections folder. This provides options for setting up different types of connection, setting up multiple connections to the same partner, setting up self connections, and so on.
In many cases, it is useful to set up a connection after a process has started, and request a connection to a partner who may or may not currently have an account. The connection request mechanism supports this requirement. Because this approach can trigger the partner to set up their own account, it is sometimes termed "viral account setup".