Hi that is the friend factor / trustee element of Steem. It has no authority to take ownership of your account, however, it cane used to identify you and help with disaster recovery in the case of a hacked account. It's described here: https://steemit.com/blockchain/@dan/steemit-releases-groundbreaking-account-recovery-solution
RE: Third Update to July 14th Security Announcement - Account Recovery Begins