account

 account  is a feature of silos, other organizations, and operating systems that use it to identify users inside their systems.

Articles

 * : "It turns out that user accounts are rarely a requirement for building a service, even though many services make it seem that way. User accounts are a great way to gather data and link it all together to create very detailed profiles. This is central to tracking users in order to commodify them and sell their attention to the highest bidder."

Twitter
Twitter has an account feature, and a UI for editing it.

2009 screenshot from the book “The Twitter Book” by Tim O'Reilly: