AJAX, with its asynchronous updates, enabled a richer user experience on the Web. It accomplished this primarily by obscuring the latency issues that brought a "clunk-ish" feel to traditional Web applications. More recently, Comet reintroduced HTTP-based "push" communications to enable Web applications with real-time events through a medium, namely JavaScript and a variety of transports (e.g., long-polling, forever frames, XHR Streaming, etc.), that is far more accessible than the "push" technologies of the late '90s, and which further lessens latency concerns felt by end users, creating a more dramatic and interactive Web experience. Both AJAX and Comet can attribute their respective successes to addressing various shortcomings of HTTP communications, whether that be with the introduction of asynchronous requests and responses or server initiated events, but it is the resolution of these trouble areas that has enabled the user experience of the document-driven Web to rapidly evolve.

Today, with the advances brought about by AJAX and Comet, we enjoy the rich Web experience delivered by applications such as Meebo, Gmail with GTalk, Google Docs, and Mint.com, but these applications, however impressive, simply represent a tipping point in user experience and, more important, still demonstrate a continued lag in the resolution of HTTP's limitations. Such applications approximate the experience afforded by the desktop, but do not deliver an experience that is as equally compelling. Granted, better "eye candy," as provided by the canvas tag or plugin-based technologies such as Adobe Flex and MS Silverlight, helps to close the gap, but even with better visual effects, latency remains the beast of burden that drags down much of the user experience delivered over the Internet, and as a result costs the industry money.

Time Is Money
There is something to be said about the old adage "time is money." Amazon.com, as reported by highscalability.com, recently stated that 100 ms of latency costs Amazon 1% of every sale. In the same article, Todd Hoff of highscalability.com reported that Google VP Marissa Mayer, at the 2006 Web 2.0 Expo, stated that a half a second delay in content delivery is correlated with a 20% drop in traffic at Google. Hoff also references a 2008 report by the TABB Group, which estimated that a 5 millisecond lag behind competing trading platforms could be as costly as $4 million in losses per millisecond. In short, users respond well to speed, as do our wallets.

Therefore, to further address latency concerns, and bridge the gap between desktop and Web applications, we must look to a new communications paradigm. Fortunately, HTML 5 Web Sockets, as defined in the Communication section of the HTML 5 specification, represent the next evolution of Web communications. Web Sockets provide not only a standard against which Comet- and AJAX -style, or any other RIA application, can be built, but also a socket, native to the browser, that facilitates network programming from the browser with efficient bi-directional (or full-duplex) communication over a single connection, eliminating many of the connection limitations that surround Comet and AJAX. The result is the promotion of the browser and its associated applications to the same citizenship on the network as that of rich desktop applications.