A mantra of many Bitcoiners that are proponents of keeping your Bitcoin solely under your own ownership by taking them off exchanges and other custodial locations. It refers to the fact that if you are not in control of the private keys to your Bitcoin holdings, you run a security risk of potentially losing your coins if the person/entity that does control them gets compromised. At 1Bitcoin.ca we encourage everyone to take proper security measures when handling their Bitcoin, because at the end of the day 1Bitcoin.ca is not a hardware wallet that you should use as cold storage.