Reference: msdnA session is defined as the period of time that a unique user interacts with a Web application. Active Server Pages (ASP) developers who wish to retain data for unique user sessions can use an intrinsic feature known as session state. For example, a user selects stocks to track and the Web application can store these values in the user's ASP session instance:
Session("Stocks") = "MSFT; VRSN; GE"ASP maintains session state by providing the client with a unique key assigned to the user when the session begins. This key is stored in an HTTP cookie that the client sends to the server on each request. The server can then read the key from the cookie and re-inflate the server session state.