Keeping track of user status

My application needs to keep track of user status (which can change in several different ways) regardless of whether or not they're logged in, and transfer all the activity log of a user if they do log in. I thought a good way to do this would be to store a "UserAccount" object in the session values. It seems like the easiest way to know if a user is logged in when a page loads, and to keep track of lots of information about a user. PRE class=c-sharp name="code"> 
if (Session["account"] == null) Session["account"] = new UserAccount(); oUserAccount = Session["account"] as UserAccount;
Are there any problems with an approach like this, or is this how people usually keep track of logged in users and their activities?
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