when a class is instantiated, storing that instance by user
You have to put it into the Session object, which is automatically managed for you.
I have to do the following, when a class is instantiated I need to store that instance by user . Since I'm working in asp.net, I was wondering if I should use some of the ways asp.net provides  to persist data between user requests. (Cache cant be because the data needs to be persistent and application state cant be because it needs to be specific to an user) or if I should look a way to store that info inside the class. And it needs to be persisted until I programatically say so