Anyway, tried out the following line of code:
string test = Request.LogonUserIdentity.User.Value;
And I see that I get a value like this: S-1-4-21-2199612581-739213201-14517828-2116
1. What exactly is this number string?
2. Is it unique to all users, possibly a way to uniquely identify users?
3. Are you still able to obtain it if the user is on a linux, mac, or some other non-windows machine OR using a handheld mobile device?