Where in the unix filesystem is the conventional location to save non-user specific data, for example data shared via nfs or ftp, or backups?

I could obviously create and use any arbitrary folder (such as /home/shared, /data or /var/data), but I'm really wondering if there are any "best" or "common" practice guidelines. The Filesystem Hierarchy Standard doesn't specify a location for shared data.

For backups, I tend to use /var/backups, but as several cronjobs write to it should it really be left for their use?