I am quickly becoming a fan of Dave Kearns and his Identity Management Newsletter in Network World. Dave discusses complex identity related issues but manages to write in a very simple and easy to read style. In his latest installment Dave talks about the difference between privacy and anonymity

I’d like to begin a discussion on anonymity as it relates to identity and technology. As noted last month, anonymity and privacy are frequently confused. One difference though is that privacy is almost always absolute (either something is private or it is not) while anonymity can be relative. If you look up “anonymity” at answers.com, you’ll find some variations in definition:

* “The quality or state of being unknown or unacknowledged.” (The American Heritage Dictionary of the English Language, Fourth Edition)

* “The quality or state of being obscure.” (Roget’s II: The New Thesaurus, Third Edition)

Anonymity is characteristic of interactions in a specific context…Like you getting a coffee from a coffee shop or leaving a comment with a made up name on a forum.

If I join a chatroom where I’m only known as “SillyGrrl” I may think I’m anonymous because I think no one knows my true identity. But the chatroom has the IP address I use to converse and my ISP knows who was using that IP address at that time. Even if I go to a library terminal or an Internet café, there are records of who used which machine and IP address at any given time. Privacy considerations may lead to those records being destroyed periodically – monthly, weekly, daily – even hourly. But anyone with the wherewithal to be watching while I connect (just as the police were watching outside the coffee shop) can shatter the façade of anonymity and connect the activity to me.

In the course of our life and through out our day, we are going in and out of various contexts in various states of anonymity. We might assume that our status in a particular context is anonymous, depending on weather we share uniquely identifiable information in the context. But as Dave point out and as outlined in this excelled video from Google tech talk, “You Are What You Say: Privacy Risks of Public Mentions“, (thanks Nitin for pointing this out) the risks to your identity, from somebody taking the time to collapse and search across, such contexts, is severe. Anybody remember the AOL Search data release fiasco. I guess, with this background, we can define privacy as a guarantee, that your data will be kept silo-ed and not shared or merged with other contexts.

The upshot – we should be careful about what we say in public forums because even with rudimentary search across contexts, people may be able to find out a lot about you. Even scarier, is somebody forming a company to just search across various public contexts on behalf of clients…In fact, I am pretty sure such companies already exist. So be careful.