If you refer others to TeamDrive you and the referred person can earn extra storage space (250MB for each person signed up?).
To refer others to TeamDrive you simply need to invite non-existing users to join your Space. The invited person then need to register using the same email address you used to invite them. Once this has been successfully completed, both you and the invited person will receive an additional 250 MB of cloud storage, until you have reached a maximum of 10 GB of free cloud storage.