HOW TO: Display the Number of Online Users for an ASP.NET Website
Solution
How to show number of online users / visitors for ASP.NET website?
(ASPDotNET FAQ) - uses Application state; example is in C#.
Tracking and Displaying Sessions/Visitors Online
(ASPNet101.com) - uses Application state; example is in VB.NET.
Membership.GetNumberOfUsersOnline Method
(MSDN)
Related Resources
MSDN: ASP.NET Application State Overview