HTTP has most often been used as a request/response protocol, leading 
  to clients polling for new data, or users hitting the refresh button in 
  their browsers. Recent web applications are finding ways to communicate 
  with web servers in realtime, pushing data from the server-side to the 
  client as soon as it is available. However, these applications at 
  present can only use a variety of HTTP mechanisms (e.g. long polling 
  requests) to communicate with web servers bidirectionally.
  
  The Hypertext-Bidirectional (HyBi) working group will seek 
  standardization of one approach to maintain bidirectional 
  communications between the HTTP client, server and intermediate 
  entities, which will provide more efficiency compared to the current 
  use of hanging requests.
  
  A general approach is preferred, with abstract semantics that can apply 
  to a large number of applications.
  
  The Web is the design space into which the solution will be deployed.
  Since the existing Web is much more complicated that it seems, the 
  working group will document how it works first, with special attention 
  to deployed infrastructure (e.g. web clients, intermediaries, 
  firewalls, NATs, web servers) and programming environments.
  
  New features will be required of clients, servers, or intermediaries 
  allowing a more scalable and robust end-to-end experience.
  
  Although multiple protocols exist as starting points, backward 
  compatibility with these protocols is not a requirement.
  
  In particular, the working group has liaised with the W3C WebApps 
  working group around the WebSockets protocol and the need to support 
  the WebSocket API; as agreed by both parties, the HyBi working group 
  will take on prime responsibility for the specification of the 
  WebSockets protocol, taking into consideration all the requirements, 
  needs and eventual concerns raised by the W3C WebApps working group. 
  The draft-hixie-thewebsocketprotocol "The Web Socket protocol" is 
  considered as the input document for the working group.
  
  Wide browser support is a goal for the bidirectional communication 
  mechanism, however the solution should also be suitable for clients 
  other than Web Browsers.  The Working Group will work to standardize a 
  generic solution that can work efficiently in as many of the deployed 
  environments as possible and in particular in all the elements of the 
  web infrastructure (e.g. web browser, generic HTTP client, HTTP server 
  and HTTP-aware intermediaries like proxies, load balancers, caches, 
  etc.) and it is not specific for just one.
  
  The Working Group should consider:
  * Implementer experience
  * Impact on existing implementations and deployments
  * Ability to achieve broad implementation
  * Ability to address broader use cases than those covered in the input 
    document
  
  The Working Group will produce one or more documents suitable for 
  consideration as Proposed Standard that will:
  * Define a characterization of the design space
  * Define a solution for the bidirectional web communication