The result is whatever you tell Crashplan to back up to the cloud gets backed up to the cloud. With the exception of Crashplan backups that go from your clients to your server.
Just like in my screenshots, you can mount as many directories/datasets as you wish, and back them all up to Crashplan cloud. The only stipulation is that you cannot backup the client backups (done in Crashplan installed on the clients).
Inside Crashplan on the server, you should see your 'storage' as whatever directory you told it to mount to. My example was /media/crashplan. This directory is actually storage on your FreeNAS box, outside of the crashplan jail. It could be a CIFS/SMB, NFS, whatever share... I use datasets for each of my client machines that I am backing up. Rsync backs up data to these datasets, these datasets are mounted in Crashplan jail, and subsequently, Crashplan jail sees them as 'local' storage and I can back them up to the cloud. So my backups are 2 fold. I utilize snapshots for that 'oops I deleted a file I shouldnt have' and anyone in my family can browse to the share, right click and get Windows previous versions (this is due to the snapshots and SMB integration, nothing to do with Crashplan at all). Then the profiles are mounted in Crashplan and uploaded to the cloud.