Teamspace guests generally participate in the teamspace at a more ad hoc or casual level than teamspace members. Depending on how your administrator has configured security and the permissions for teamspace guests, they may not be able to see all of the same objects in the teamspace as other members. By default, guests cannot add to or change the content in the teamspace.
You can add groups of users from your enterprise as teamspace guests. Anyone who is a member of that group (auditors, managers, etc.) can then enter the teamspace and monitor the content as needed, without being an active member of the teamspace.
Adding a person or group as a guest
Use shift-click to select a range of names. Use ctrl-click to select multiple names.