A mock stock price subscription service using SignalR and Rx

A (semi-)realistic stock price subscription service would have these key requirements:

• It won't produce price updates for a stock that no clients are watching
• The price updates can be randomly generated for the simulation, but...
• Multiple clients watching the same stock should see the same prices.

Can I use SignalR and Rx to do this effectively?

See it in action, or read the blog post.