In addition to Solution 1:
Please see the explanation of push technology:
http://en.wikipedia.org/wiki/Server_push[
^].
Isn't that obvious why traditional client-server model and pull technology predominantly used on the Web is bad for such a basic application as a chat? The client side cannot have notification on any replies on the thread and would have to do permanent polling of the server side, which is too wasteful and not enough responsive at the same time.
SignalR is one of the workaround solutions. Please see:
http://en.wikipedia.org/wiki/SignalR[
^],
http://www.asp.net/signalr[
^].
For some more explanations, please see my past answer, more detailed one:
Application 'dashboard' for website accounts[
^].
—SA