Mine got enabled today.
Yeas it's 100GB free storage, but with a couple of caveats.
Certain limitations on the Free version.
You don't have instant access to your files, you request access then receive an email 3-5 hours later. It's aimed at storage/backup purposes, not sharing/instant access.
You can't set your own backup schedule, it's either every 4hrs, 12hrs or 24hrs.
FAQ's in the Wiki
| Planetside 2: PapaSmurf
| Yahoo Messenger: Gazanimal