 <p>Is this just an example, or the real application?</p> <p>In trading room environments, market data applications are extremely sensitive to delays of even a few milliseconds, and a lot of time and money is invested to minimise delays.</p> <p>This makes the set of technologies you're talking about completely inappropriate; C/C++/Java apps communicating over raw TCP sockets or through a high performance middleware are the only way to get the necessary performance. Internet distribution has unpredictable delays.</p> <p>Of course, if you're talking about the low-end of the market, where 'realtime' means the user won't get bored waiting for a response, as opposed to liveness of data, then there are many possible technologies. AJAX may be suitable, using either XML or JSON payload.</p> <p>What type of data source do the quotes come from? Is it's a database, XML/JSON AJAX makes sense; if it's message-orientated middleware, then sockets are much better.</p> <p>Do you need to have real-time updates, and is it acceptable for individual updates to get aggregated?</p>