A BBC ID account will be used to "personalise and localise" its services for those who register, the Corporation says.
Since the start of September anyone watching BBC programmes on iPlayer has had to have a valid TV licence. Although the Beeb says the information gathered through a BBC ID account won't be used to enforce the closure of the so-called iPlayer loophole, the inclusion of people's postcodes makes it a distinct possibility in the future.
Before this month's rule change, a TV licence was only needed for watching live TV. If you only watched programmes on iPlayer after they had been broadcast, you could avoid paying the £145.50 annual licence fee.
The BBC says around seven million people in the UK currently have a BBC ID account.
BBC director general Tony Hall says: "By learning about what you want and like we can take you to more of the great programmes you love, stories you might be interested in and content you might otherwise never have discovered."