What is an "unidentified caller"?
Anyone who dials in to the audio conference using a telephone but doesn't enter an Audio PIN is known as an "unidentified caller". This means that GoToMeeting cannot identify them by name, so it views them as a separate participant. Organizers will see those individuals appear in the Attendee list as "Caller [X]".
How it works
When an attendee connects to audio via Computer audio (mic and speakers), GoToMeeting automatically detects their identity. But if an attendee uses Phone audio (i.e., dials in with telephone) to connect to session audio, then GoToMeeting needs some way of identifying who the phone call is coming from and detecting that they are the same participant who joined the session from their computer or mobile device.
In order to do this, GoToMeeting provides a unique Audio PIN to each attendee who selects Phone audio. Once they enter it, GoToMeeting knows who they are. However, if the attendee dials in but does not enter their Audio PIN, then GoToMeeting has no way of recognizing them. Therefore they are seen as "unidentified" and listed as a separate participant.
If the caller later enters their Audio PIN, then GoToMeeting will recognize them as an existing attendee and "merge" them with their existing entry in the Attendee list.
Enable/disable "unidentified callers"
Unidentified callers is a feature that must be enabled by an account admin. Once it has been enabled for an account, all organizers will automatically have it used in their meetings.