The /afs tree contains shared filesystems. /afs/hcoop.net is our piece of the AFS-o-sphere, but is not (yet) listed in the global CellServDB. See about volumes in the openafs docs for information on the standard naming scheme for volumes when adding new volumes
Subdirectories include:
/afs/hcoop.net/user, the home of home directories
/afs/hcoop.net/user/U/US/$USERNAME, $USERNAME's home directory
/afs/hcoop.net/old/user/U/US/$USERNAME, $USERNAME's daily backup of their home directory
/afs/hcoop.net/common/etc, the home of non-platform-specific fun stuff like DomTool