I am looking to accomplish 2 way communication over http between a .Net service (WCF SOAP or REST, both options are open) hosted on IIS 7 and Windows Forms Client running on Windows 7. WebSockets are not supported with IIS 7 and all other Comet techniques allow only the web server to push data to client and not the other way around. The client will be very chatty, and there are thousands of clients, so I want to avoid creating a new HTTP request for each message to the server, though that is the last option. Is there any way to do this ?