Shadow profile

A shadow profile means that if someone who doesn't know who you are includes you in their analytics. Ie. if they don't know who you are they may assign you a large number such as "user2013072988891245". Then whenever they re-identify that user they use this profile for stats. If the user one day logs in with a name they can merge the profiles and know who the shadow profile belongs to. Also if the user never reveals who they are by comparing the profiles habits perhaps it's possible to identify who is behind the shadow profile.