Server Side Events (SSE) vs WebSockets

Web sockets are bidirectional channel in between browser and server and mostly suitable for application like  gaming, It has complex APIs and works on custom protocols
Server Side Events (SSE) are unidirectional (server to client ) channel , light weight , uses HTTP protocol and very much stable for building application like stack tickers.

More References 

• http://html5doctor.com/server-sent-events/
• http://www.html5rocks.com/en/tutorials/eventsource/basics/