Catching user switching and getting current active user from root on linux

[mpnordland]

I think I do understand multiuser systems, although I'm sorry I did
not make my self clear. Yes, I understand that there can be multiple
people logged in, and yes if you really wanted to, you could login as
yourself as many times as you want. This is not a server based
program, it is intended for use in a normal environment. The people
using it will probably not be logging in multiple times as themselves,
or someone else. The problem I have is I want monitor what sites the
user visits, I need to know what sites were accessed by which user.
So, a way to find which user is requesting what url is what I want.
Have I passed the Turing test?