As you interact with other Groove users—adding them as contacts and working with them in workspaces—Groove stores information about them in the Contact Manager, also known as the Known Groove Contacts list. This list is different from the list of contacts on the Contacts tab of the Launchbar, to which you add contacts directly. The Contact Manager list includes those contacts, but also includes users who get added indirectly because of interactions such as the following:
You receive a message from a Groove contact.
You send a message to a Groove contact.
You join a workspace. (All other members of that workspace are then added to your Known Groove Contacts list.)
Someone joins one of your workspaces.
As previously mentioned, ...