Web 2.0 is a term you'll hear used to describe the emergence of a new paradigm for Web use and interaction. Web 1.0 (which still describes much of the World Wide Web as we know it today) depends on standard Web servers that proffer content to clients, clients with Web browsers that grab content from servers and limited communication at best from clients to servers, usually mediated by input forms or semi-capable web-based applications.
Web2.0 views the Web as a two-way street where clients read some static data, but where they can also create active data of their own and even interact with one or more other people through a Web-based interface. Web 2.0 also views the Web as a programming environment on top of which developers can create powerful, capable software and services. APIs, such as those included in .NET, J2EE and numerous other environments help multiple independent applications to work together to pull this off.
Where's XML in this picture you ask? Explicitly, it's nowhere, but implicitly, it's everywhere. Many of the APIs that help to make distributed applications able to communicate use XML (SOAP, for example). The same is true for APIs that enable data exchange, security, resource identification and use, and many more elements.
Tim O'Reilly's "What is Web 2.0?" article uses a table of examples that compares and contrasts Web 1.0 and Web 2.0 that helps to illustrate the differences between the two worlds pretty effectively. Here's a chunk of that information to help you get a more complete picture:
|Web 1.0||Web 2.0|
The examples help to illustrate that the notions of free back-and-forth, pull as well as push, lots of interaction and flexibility, and large scale activity and cooperation are all involved in bringing the more modern view of the online universe to life.
Digging more deeply into Web 2.0 shows that XML is involved in nearly every exemplary technology and in all the programming tools that give Web 2.0 its meaning and potential significance. But don't expect to see a noticeable "version upgrade" from 1.0 to 2.0. It's something that is already at work in many of the things we see and activities we undertake online. Web 2.0 is bound to become more and more descriptive of the ways things work as XML-based tools and technologies blow the lid off what's possible with modern interactive Web-based software.
For further reading on Web 2.0, you could do a lot worse than to visit Joshua Porter's Introduction to Web 2.0 at Squidoo.com. It not only includes a nice description, it also includes annotated links to all the important articles and work on this subject. Use it as a great jumping off point to dig deeper into this subject matter, if you like.
About the author
Ed Tittel is a full-time writer and trainer whose interests include XML and development topics along with IT Certification and information security topics. E-mail Ed at firstname.lastname@example.org with comments, questions or suggested topics or tools for review.