One of the selling points of a web framework like ASP.NET Core is the ability to provide a dynamic app, customized to individual users. Many apps have the concept of an “account” with the service, which you can “sign in” to and get a different experience.
Depending on the service, an account gives you varying things. On some apps you may have to sign in to get access to additional features, and on others you might see suggested articles. On an e-commerce app, you’d be able to place orders and view your past orders; on Stack Overflow you can post questions and answers; on a news site you might get a customized experience based on previous articles you’ve viewed.