Web 3.0 is a different way of building applications and interacting on the web. The core model of web 3.0 states that entire World Wide Web will be seen as a single database. Many tools are being developed through which interactivity between different websites with different data can be enhanced. Prediction is that Web 3.0 will ultimately be seen as web applications which are pieced together.

There are a number of characteristics of these applications: they are relatively small, the data is in the cloud, they can run on any device- PC or mobile phone, they are fast and customizable. Furthermore, the applications are distributed virally: literally by social networks or by email.

That's a very different application model than we've ever seen in computing. However, there is still considerable debate as to what the term Web 3.0 means, and what a suitable definition might be.

Critical step towards web 3.0: Transforming the Web into a database
The first step towards a "Web 3.0" is the emergence of "The Data Web" as structured data records are published to the Web in reusable and remotely query- able formats, such as XML, Resource Description Framework (RDF) and micro formats. The Data Web enables a new level of data integration and application interoperability, making data as openly accessible and linkable as Web pages. The Data Web is the first step on the path towards the full Semantic Web. In the Data Web phase, the focus is principally on making structured data available using RDF. The full Semantic Web stage will widen the scope such that both structured data and even what is traditionally thought of as unstructured or semi-structured content (such as Web pages, documents, etc.) will be widely available in RDF and OWL semantic formats.

From Web 2.0 to 3D Spaces
Another possible path for Web 3.0 is towards a 3 dimensional vision championed by the Web3D Consortium. This would involve the Web transforming into a series of 3D spaces, taking the concept realized by “Second Life” still further. This will open up new ways to connect and collaborate using 3D shared spaces.

Web 2.0 "is a decade and not a technology" - it's more about defining the character of each era, rather than trying to define a Web era as a set of technologies. So in those terms, if Web 2.0 is equivalent to social web, then Web 3.0 will be the "intelligent web".

A traditional web service is a very thin client -- the Browser displays images relayed by the server, and every significant user action goes back to the server for processing. The result, even on a high-speed connection, is online applications that get stuck when you start to do any significant level of user interaction. Most of us have probably had the experience of using a Java-enabled website to do some content-editing or other task. The experience isn’t just unpleasant -- it’s so bad that non-geeks are unlikely to tolerate it for long. It’s a big barrier to use of more sophisticated Web applications.

Enter Web 2.0, whose basic technical idea is to put a user interaction software layer on the client, so the user gets quick response to basic clicks and data entry. The storage and retrieval of data is conducted asynchronously in the background, so the user doesn’t have to wait for the network.

The more people start to depend on their web applications, the more unacceptable these connectivity outages will be. That’s why mobile web applications need a different architecture -- they need both a local client and a local cache of the client data, so the app can be fully functional even when the user is out of coverage. Call it Web 3.0.

When you’ll send an e-mail through your mobile application, it will keep a local copy of your e-mail inbox, so you can work on it at any time. When you send a message, it looks to you as if you’ve sent it to the network, but actually it just goes to an internal cache in the device, where the message sits until a network connection is available. Same thing with incoming e-mail -- it sits in a cache on a server somewhere until your device is ready to receive. The system looks instantaneous to the user, but actually that’s just the local cache giving the illusion of always-on connectivity.

This is the way all mobile apps should work. For example, a mobile browser should keep a constant cache of all your favorite web pages (for starters, how about all the ones you’ve bookmarked?) so you can look at them anytime. Of course, once we’ve put the application logic on the device, and created a local cache of the data, what we’ve really done is create a completely new operating system for the device.