Examples of applications where messages are pushed from a server and display on clients immediately

Question

I'm trying to find an example to show where data is sent from a server and is pushed to a/multiple clients which are updated immediately, i.e. the client doesn't make requests for updates. It doesn't matter whether we're talking mobile, desktop or whatever. An even better example would be where there were multiple recipients for the same message. It doesn't matter what the data is or the context it's used in, only the immediacy of receiving it. I was thinking that there might be some example in finance and the stock markets, but I haven't been able to find any through googling.

IM clients are a great example of this and are on my list of one ;)

If anyone works on applications of this nature or knows of particular implementations, can you give me a quick run down of the use case and if it's commercial software the name of the software.

This is all basically for research purposes so doesn't have to be particularly detailed.

If anyone can help, thanks.

EDIT - Granted the question is vague. Doing some concepting so need some examples. There must be a huge amount of apps that work like this.

Answer 1

The screen command in linux can have multiple screen attached to one session. So a change in one is pushed to all the others.

The

  nc 

command might also be useful, as far as I know it doesn't support connections from multiple clients, but it is a simple example.

In the programming world the observer pattern is probably what you want.

http://en.wikipedia.org/wiki/Observer_pattern

Answer 2

Internet Relay Chat (IRC)

as people are constantly pumping chat messages and events to the server (channel), everybody else connected gets updated.

Answer 3

Server-based network games

Any game that connects to centralised server for real-time gaming, requires server to feed game event data to client gamers.

Answer 4

From commercial point of view you can be interested in this product. It uses the push technology where data is pushed from the server and displayed on the client terminal.

Answer 5

The wikipedia article Push technology can be a great starting point:

Synchronous conferencing and instant messaging are typical examples of push services. Chat messages and sometimes files are pushed to the user as soon as they are received by the messaging service. Both decentralised peer-to-peer programs (such as WASTE) and centralised programs (such as IRC or XMPP) allow pushing files, which means the sender initiates the data transfer rather than the recipient.

Email is also a push system: the SMTP protocol on which it is based is a push protocol (see Push e-mail). However, the last step —from mail server to desktop computer— typically uses a pull protocol like POP3 or IMAP. Modern e-mail clients make this step seem instantaneous by repeatedly polling the mail server, frequently checking it for new mail. The IMAP protocol includes the IDLE command, which allows the server to tell the client when new messages arrive. The original BlackBerry was the first popular example of push technology for email in a wireless context.

Another popular type of Internet push technology was PointCast Network, which gained popularity in the 1990s. It delivered news and stock market data. Both Netscape and Microsoft integrated it into their software at the height of the browser wars, but it later faded away and was replaced in the 2000s with RSS (a pull technology).

Other uses are push enabled web applications including market data distribution (stock tickers), online chat/messaging systems (webchat), auctions, online betting and gaming, sport results, monitoring consoles and sensor network monitoring.

The above article contains many links which I haven't duplicated here.

Answer 6

StackExchange itself does this when it notifies users that new responses have been posted as they're editing their own response.