Computer databases that store information about individuals comprise a person's VirtualIdentity.
These are becoming more and more converged--for instance, NumberPortability?, DotNetPassport, LibertyAlliance.
Makes IdentityTheft easier but will allow less of a stack of cards (visa, transit, health, video store, gym, work card etc etc) to be carried around when you can have one SmartCard? or DigitalWallet? that points to a central store of information. Less form filling (paper or online) would be needed and true SingleSignOn? would be possible. LightweightDirectoryAccessProtocol (LDAP) servers such as is used in companies for authentication could be pointed to your central online persona to know who you are.
For example MS ActiveDirectory can integrate with Passport it would be interesting to see if OpenLDAP can be integrated with LibertyAlliance. For instance in Malaysia they have a combined (real) passport, Drivers License and bank info on one card. These cards often have short range wireless capability so just need to be brought near a transponder, not swiped; example: transit cards in HongKong.
MicroSoft is also looking at MyLifeBits? to store lots of info such as pictures about yourself systematically online.
ATM transactions (and now MicroPayments and m-commerce) leave a history and E911 allows mobile phone operators to track your position to within a few feet (with GlobalPositioningSystem and similar. Assisted GPS allows triangulation even indoors). Though initially was for emergency calls, it is also being used commercially to provide LocationBasedServices?. This will allow targeted marketing and benefits consumers but the downside is many companies will have access to your movements. Most phones will have an option to turn this feature off (except for 911 tracking) but will probably be left on most of the time. Services such as OnStar? can track your vehicle. Face and posture recognition allow video cameras to identify individuals also and since these are becoming ubiquitous, if all this information is correlated an extensive trace of who, what you are or have done and where you are or have been can be stored.
See also AnonymousIdentity, OnlineIdentity