Hi,
I want to develop ASP.NET C# based MMOG (Massively multiplayer online game). I would be using ASP.NET Ajax control kit, jquery and MS SQL server 2005.
Q.1)How feasible .NET 3.5, ASP.NET with C# in handling thousands of users simultaneously.
I would also incorporate ASP.NET ajax based chatting system with chat rooms alongside the MMOG.
Q.2) Do you know any of the sites (MMOG) using ASP.NET ?
Q.3) What are the best practices for Chatting System as mentioned above?
ASP.NET can handle it with the proper server configuration, hardware, and performance considerations when creating the application.
I tried to do some googling and didn't find anything right away, but I'm sure that there are some out there.
For the chat piece you might look at a product such as CuteChat that already exists and has been tried and tested for a long time.
ASP.NET and MSSQL 2005 definitely have no "built in" scaling problems. You will have to take care to build you application right and be prepared to dish out some money for proper hardware.
See for example the hardware setup that is scheduled to tackle the stackoverflow load.
I would think about using Silverlight instead of the AJAX-based stuff. From a UI perspective you'll be able to do a lot more.
Plenty of bigass websites running ASP.NET. I'd HIGHLY recommend using the new MVC framework, as it reduces the complexity of ASP.NET websites greatly.
ViewState will end up being your end game raid boss unless you disable it or switch to ASP.NET MVC.
Maybe today you start with a html/javascript/jquery UI and tomorrow you throw on a fancy Silverlight or Flash UI.
AjaxControlToolkit is pretty bloated and kinda hard to customize. With an MMO, speed is going to be a priority, so you'll want as much control over your postbacks as possible.
You also might try looking into Silverlight for your front end. It integrates well with the .NET environment, and would be a lot easier to develop your interactive pieces with.