Users online, no membership, eg, improving

Dear Colleagues (sorry my bad english),

I Implemented the following mechanism for system that show users online in a list, code:
http://www.c-sharpcorner.com/UploadFile/munnamax/whoseonline08042007062609AM/whoseonline.aspx

I made the junction with my system and it worked, but hardly made ??any change, for not understanding the logic very well, because the codes are not discussed.

First, someone who knows this kind of logic? can explain to me about this class WhoseHandler.cs (i dont want use this class, i want integrate the codes in my Default.apsx.cs).

In this example of code link above, when the user will no longer appear as logged in? (I want know if this use the sessions opened to show the users online, i want understand how this work) seen in "WhoseOnline" function the command:

while(whosOln.MoveNext())
{
HttpContext.Current.Response.Write(whosOln.Value +"<br>");
}

Another doubt is that I could make use of the mechanism using and including WhoseHandler.cs in my application, but I think it will be very "frankstein" (eg, I would just include the commands that WhoseHandler.cs on my default.aspx. cs), wanted to integrate better, I'm not used to search codes ready and fit in my projects, I started researching things like this now - and it is a different way of organizing the code I use, I could not adapt very well. Any suggestion is welcome.

detail, I intend to continue with this implementation because it was the only one who found it viable to my system, because i dont use membership.

Thanks in advance.