It’s like the Electronic Frontier Foundation is Captain Obvious? It says web-sites fingerprint browsers to identify the users.

The website anonymously logged the configuration and version information from each participant’s operating system, browser, and browser plug-ins — information that websites routinely access each time you visit — and compared that information to a database of configurations collected from almost a million other visitors. EFF found that 84% of the configuration combinations were unique and identifiable, creating unique and identifiable browser “fingerprints.” Browsers with Adobe Flash or Java plug-ins installed were 94% unique and trackable.

A login is supposed to belong to an individual. Web technologies wanting to honor transactions sent by web browsers which have sent a successful login typically do so by granting that browser a token. Don’t want to enable cookies? Fine. Go somewhere else. As long as you want to use my application, you’ll have a cookie I’ll associate with a username.

All this other stuff is for fingerprinting browsers without using a login. Or maybe to identify who is using the same login? I’ve got different browsers for different logins on the same sites.
🙂