Anonymity and Pseudonymity
One of the questions that your business should understand clearly is what level of identity is needed for which relationships. For many purposes, you need specific, authenticated, and detailed identity information from your partners, suppliers, and employees. You may be able to provide service to customers, however, as they remain anonymous or at least pseudonymous.
True anonymity is not realistic for most online services, since they probably have to at least maintain some kind of user state and that requires telling which individual HTTP requests are related. Consequently, the user is not anonymous, because you can distinguish between different users. This leads to the concept of pseudonymity .
In a pseudonymous system, users are uniquely identified, but other identifying information is not shared. Pseudonymous systems give subjects a unique ID with which attributes, rights, and privileges can be associated. Pseudonymity is a term usually reserved for people, since the unique ID and its associated attributes, rights, and privileges constitute an identity as we've defined it. Pseudonymity implies that this identity cannot be tied to other identities that the subject might have without the subject divulging the connection.
Businesses should ask, "What identifying information is required?" early in the design process for an online service. I say "businesses" because this is almost always a business decision, not a technology decision. In keeping with our concept ...