| "Why would I route the product of JS based chat through a third party when it could just communicate with the server it got the HTTP from in the first place ?" I'll take a stab at it with an anecdote. First it can be used for more than chat. Anything where a message bus would meet the need could work on top of this. The project I work on uses pubnub(http://www.pubnub.com/) instead of appengine's channel api because we wanted a reliable way to broadcast to several listeners. Where at the time the channel api would only do point to point(still does), and if you wanted broadcast you had to maintain connection state with all listeners somehow. So you would have to invent your own keep-alive protocol(not my cup of tea) etc... So now , when the server needs to notify all listening clients of something, a json message is put in a scheduled task queue, and the call goes out to pubnub in a few ms and arrives to clients a few ms after that. It's pretty impressive. Looks like spire.io provides similar services. essentially a cloud based message bus that supports broadcast/fan out. pubnub is supposedly servicing 100K messages per second now. And I would guess it's not just chat.(http://techcrunch.com/2012/03/21/as-developers-seek-more-int...) |