The Arab Spring revolution was sparked and fuelled through social media sites like Facebook and Twitter. Over the next few days, social media went from being just a means of interacting with family and friends to a weapon that empowered the people and brought about a significant change in the world. Everyone noticed the power of the people and people noticed what social networks were capable of. At the heart of it all was the technology that made all this possible, the technology that removed all the barriers to communication and spread the word faster than wildfire. This is the power of real-time web!
On the Web, we have been habituated to sites and applications where we click on a link or a button, or change some input and perform some action, and it causes some change in the page. But if we leave our twitter page open for a while, we get alerts when we receive new tweets, even without performing any action (shown in the next screenshot). This is what we mean in general when we say "real-time web".
Real-time updates on Twitter
Wikipedia introduces real-time web in these words:
The real-time web is a set of technologies and practices that enable users to receive information as soon as it is published by its authors, rather than requiring that they or their software check a source periodically for updates.
This "set of technologies" is one of the hottest trends on the Web. Over the next few pages, we will get familiar with these technologies and see their use in various applications.