Over the last several years, we've witnessed a dramatic shift in how people use the Web. What started as interactive Web applications under the moniker "Web 2.0" has become a firestorm of social applications like Facebook, Twitter, and Foursquare, among others. But underlying these changes is something even more important than the "social" Web: the "real-time" Web.

The real-time Web is a radical shift in how people use the Internet: rather than simply viewing static pages, or even interacting with a Web site, the real-time Web uses dynamic streams of information to present contextual, relevant experiences to user.

These dynamic streams of information include such diverse data flows as Twitter streams and Facebook news to RSS feeds of product recalls. Many of these information streams are enabled and supported by APIs since programmatic access to the data is critical to its reuse in various guises.

Information reuse is a major premise of the real-time Web since much of the information available is not nearly as interesting by itself as it is in combination with other data streams. Further, this reuse is often highly personal since what you want from the information stream and how you want it mixed with other data is different from what I want.

Making streams "real-time" skews design to one favoring interrupts over polling. Protocols like PubSubHubBub and services like push.ly are created with the explicit purpose of taking polling-based technologies like RSS and giving them an interrupt-driven façade.

I think we've only begun to see and imagine the world that will result from real-time access to information streams that are recombined in myriad ways. This is especially true when you start to consider the possibilities that personal data, properly protected and permissionsed, adds to the mix.