[MUSIC] So let's talk about the characteristics of web applications, starting from the early days and what they look like now. Let's start with Web 1.0 architectures. Now, these are characterized by static web pages, and here we see the first web-based business models. And by static web pages, I mean websites that simply pushed information out with very little user interactivity. The first web browser was called the Worldwide Web, and it was developed by Tim Berners-Lee in 1990. But the real explosion in popularity of web applications started with the release of the first graphical, or GUI-based web browser, which was called Mosaic. And this was released in 1992. Mosaic was created at the National Center for Super Computing Applications at the University of Urbana-Champaign. And many of those who worked on Mosaic later developed what was called the Netscape Navigator browser that was released in 1994. This also led to the creation of the first Internet based company which was called Netscape. Now over time, the Netscape browser evolved into the Mozilla Firefox browser that many of us now use today. Now by the mid-1990s, Microsoft had entered this area and engaged with Netscape in what were called the browser wars. This led to the emergence of Microsoft Internet Explorer as the predominant web browser during this time period. Web 2.0 is characterized by more interactive websites. And this enabled things like social networking, online commerce, WIKIs like Wikipedia, and some lightweight collaboration you see with some of the document sharing capabilities. The Ajax technology, which we'll talk about more, shortly, as well as in a later lesson, was the primary enabler of this interactivity. What Ajax does is it allows for web pages, and thus, web applications, to change content dynamically, without the need to reload an entire page. So this made web applications much more responsive. In other words, they were more like the desktop applications that users were used to seeing when they used their personal computers, when they interacted with an application on their personal computer. So here we see, for the first time, this line blurring between web applications and desktop applications, in terms of the user experience. Web 3.0, here we see the emergence of the intelligence web. And this involves this ubiquitous computing where you're always connected to the Internet. Some of the things that are enabled by this intelligent web, recommender systems, the semantic web where semantic information is attached to web content, so that you can reason more over what that content contains. Much more mobile friendly, web environment, and the Internet of things, which we've discussed earlier, where everything can be connected to the Internet, every type of device you can think of is connected into the Internet. So what do I mean by intelligent web? What I mean is that this is machine-facilitated understanding of information on the Worldwide Web. This happens by attaching metainformation, and we'll see how later, to web page. This is the exciting future that we have in store for us in the development of web applications, these intelligent web applications. Now, what were the enablers of Web 2.0 and Web 3.0 technologies? As I mentioned, the first of these is Ajax, and Ajax stands for asynchronous, that's the A. And what that means is that your website doesn't block and wait for a content to be returned from a server. You can continue to interact with the website until that content is available, and then asynchronously, it's delivered to your browser. At the time, XML is what the X stood for. Now it's more common to see the use of JSON and then JavaScript is what the J is there. Now, the term, it's no longer an acronym, Ajax is no longer an acronym. It just means this asynchronous delivery of content. And again, we'll see how to use this in a later lecture. Now web service interoperability, and this REST-based services, is the other thing that really helped spawn the growth of Web 2.0 and 3.0 architectures. The ability to use services from other websites. The next thing is cloud computing, the ability to have infrastructure, platforms, software as a service capabilities. We see the emergence of Amazon Web Services and Salesforce, these types of companies that allow for users to easily use IT services that are external to their own operation. And this really facilitated the growth of web applications, and the very powerful mobile platforms. The mobile phones we have now are equivalent to the super computers of just a couple of decades ago. And so these mobile phones with location awareness capabilities, these types of things really made Web 2.0 and 3.0 applications much richer, I should say. And then this metadata that I mentioned, and linked data, where you're linking data between different websites, and this machine processing of information by intelligent agents. This, I see really as the future of what web applications will look like. And then again, web-enabled devices from your doorbell, to your refrigerator, to your car, everything will be web-enabled as we move forward.
